Author 
Message 
TAGS:

Hide Tags

Senior Manager
Joined: 20 Mar 2018
Posts: 492
Location: Ghana
Concentration: Finance, Real Estate

Re: Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
05 Dec 2018, 00:43
VeritasKarishma wrote: Staphyk wrote: 2 men and 3 women can finish a piece of work in 10 days. while 4 men can do it in 10 days. how many days can 3 men and 3 women take to finish the same work?? Please help me solve this Karishma Sent from my iPhone using GMAT Club Forum mobile app2 men and 3 women finish it in 10 days 4 men (2 men + 2 men) finish it in 10 days So 3 women are equivalent to 2 men. Then 3 men and 3 women are equivalent to 3 men and 2 men i.e. 5 men. Now, 4 men complete the job in 10 days. So 5 men will take 10*(4/5) = 8 days (fewer days will be taken so multiply by 4/5, the fraction less than 1) For more on this method, check this post: https://www.veritasprep.com/blog/2015/1 ... madeeasy/Wow! got it ,Thanks very much Sent from my iPhone using GMAT Club Forum mobile app



Senior Manager
Joined: 20 Mar 2018
Posts: 492
Location: Ghana
Concentration: Finance, Real Estate

Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
05 Dec 2018, 12:34
 Brand X  Brand Y MilesperGallon  40  36  CostperGallon  $0.80  $0.75  The table above gives the gasoline costs and consumption rates for a certain car driven at 50 miles per hour, using each of two brands of gasoline. How many miles farther can the car be driven at this speed on $12 worth of brand I gasoline than on $12 worth of brand Y gasoline? Hello Karishma am totally confused on this question any efficient method? Thank you Sent from my iPhone using GMAT Club Forum mobile app



Senior Manager
Joined: 20 Mar 2018
Posts: 492
Location: Ghana
Concentration: Finance, Real Estate

Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
05 Dec 2018, 13:22
Again, In a manufacturing plant, it takes 36 machines 4 hours of continuous work to fill 8 standard orders. At this rate, how many hours of continuous work by 72 machines are required to fill 12 standard orders? This how I solved it 36machines——8orders——4hrs 72machines——12orders—— Xhrs Now,Xhrs=4*(72/36)*(12/8) =12hrs But was wrong multiplied by 72/36 since machine increased so fraction (>1) same applies to the orders, Where did my logic go wrong. Also,when is it appropriate to use the chain rule W1/M*T= W2/M*T Thank you Sent from my iPhone using GMAT Club Forum mobile app



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 10229
Location: Pune, India

Re: Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
06 Dec 2018, 02:32
Staphyk wrote:  Brand X  Brand Y MilesperGallon  40  36  CostperGallon  $0.80  $0.75  The table above gives the gasoline costs and consumption rates for a certain car driven at 50 miles per hour, using each of two brands of gasoline. How many miles farther can the car be driven at this speed on $12 worth of brand I gasoline than on $12 worth of brand Y gasoline? Hello Karishma am totally confused on this question any efficient method? Thank you Sent from my iPhone using GMAT Club Forum mobile appHere you go: https://gmatclub.com/forum/thetableab ... l#p2185231
_________________
Karishma Veritas Prep GMAT Instructor
Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 10229
Location: Pune, India

Re: Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
06 Dec 2018, 02:37
Staphyk wrote: Again, In a manufacturing plant, it takes 36 machines 4 hours of continuous work to fill 8 standard orders. At this rate, how many hours of continuous work by 72 machines are required to fill 12 standard orders? This how I solved it 36machines——8orders——4hrs 72machines——12orders—— Xhrs Now,Xhrs=4*(72/36)*(12/8) =12hrs But was wrong multiplied by 72/36 since machine increased so fraction (>1) same applies to the orders, Where did my logic go wrong. Also,when is it appropriate to use the chain rule W1/M*T= W2/M*T Thank you Sent from my iPhone using GMAT Club Forum mobile appYou need to find the number of hours required. When the number of machines go up from 36 to 72, considering everything else constant, will you need more hours or fewer hours? Since the number of machines is more now, you will need less time. More machines will work simultaneously so the work will get completed faster. So you need to multiply 4 by (36/72), the fraction less than 1. As for orders, from 8 they have gone up to 12 i.e. the work needed to be done has increased. When work to be done increases, keeping everything else constant, will you need more hours or fewer? Since more work has to be done, you need more hours. So you multiply by 12/8, the fraction greater than 1. 4 * (36/72) * (12/8) = 3 hrs Answer (A)
_________________
Karishma Veritas Prep GMAT Instructor
Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >



Senior Manager
Joined: 20 Mar 2018
Posts: 492
Location: Ghana
Concentration: Finance, Real Estate

Re: Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
06 Dec 2018, 05:41
VeritasKarishma wrote: Staphyk wrote: Again, In a manufacturing plant, it takes 36 machines 4 hours of continuous work to fill 8 standard orders. At this rate, how many hours of continuous work by 72 machines are required to fill 12 standard orders? This how I solved it 36machines——8orders——4hrs 72machines——12orders—— Xhrs Now,Xhrs=4*(72/36)*(12/8) =12hrs But was wrong multiplied by 72/36 since machine increased so fraction (>1) same applies to the orders, Where did my logic go wrong. Also,when is it appropriate to use the chain rule W1/M*T= W2/M*T Thank you Sent from my iPhone using GMAT Club Forum mobile appYou need to find the number of hours required. When the number of machines go up from 36 to 72, considering everything else constant, will you need more hours or fewer hours? Since the number of machines is more now, you will need less time. More machines will work simultaneously so the work will get completed faster. So you need to multiply 4 by (36/72), the fraction less than 1. As for orders, from 8 they have gone up to 12 i.e. the work needed to be done has increased. When work to be done increases, keeping everything else constant, will you need more hours or fewer? Since more work has to be done, you need more hours. So you multiply by 12/8, the fraction greater than 1. 4 * (36/72) * (12/8) = 3 hrs Answer (A) got it now ,Thank you Sent from my iPhone using GMAT Club Forum mobile app



Manager
Joined: 17 Jul 2017
Posts: 245

Re: Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
08 Dec 2018, 10:43



Current Student
Joined: 04 Jun 2018
Posts: 155
GMAT 1: 610 Q48 V25 GMAT 2: 690 Q50 V32 GMAT 3: 710 Q50 V36

Re: Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
09 Dec 2018, 04:33
https://gmatclub.com/forum/inthexyco ... 47203.htmlCan you help me understand the concept of equidistant points? What does this exactly mean? More specifically i cannot understand case 2 mentioned in the discussion. Case 1) Either a line that is equidistant from the two points must be passing from the the gap between the two points. In this case every point on the line will be equidistant from each of the two given points.OR Case 2) The line that is equidistant must be parallel to the line joining the two points (7, 7) and (1, 11). But this case is applicable only when the perpendicular distance of the Line from point is discussed How is case 2 applicable? If there are 2 points on a line : A and B. We draw a parallel line CD. In this case not every point in the line CD will be equidistant from A and B. Looking forward to your opinion. Regards Nitesh



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 10229
Location: Pune, India

Re: Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
10 Dec 2018, 00:00
nitesh50 wrote: https://gmatclub.com/forum/inthexycoordinatesystemwhatistheslopeoftheline47203.html
Can you help me understand the concept of equidistant points?
What does this exactly mean? More specifically i cannot understand case 2 mentioned in the discussion.
Case 1) Either a line that is equidistant from the two points must be passing from the the gap between the two points. In this case every point on the line will be equidistant from each of the two given points.
OR
Case 2) The line that is equidistant must be parallel to the line joining the two points (7, 7) and (1, 11). But this case is applicable only when the perpendicular distance of the Line from point is discussed
How is case 2 applicable? If there are 2 points on a line : A and B. We draw a parallel line CD.
In this case not every point in the line CD will be equidistant from A and B.
Looking forward to your opinion.
Regards Nitesh Nitesh, Distance of a point from a line is assumed to be the perpendicular distance. If the line passes through the midpoint of two points, its perpendicular distance from both points will be equal (as explained by walker here: https://gmatclub.com/forum/inthexyco ... ml#p452751) So one way is that the line passes through origin and through the midpoint of PQ. Alternatively, the line could be passing through origin and parallel to PQ. Then perpendicular distance from P to the line and perpendicular distance from Q to the line will be equal (perpendicular distance between two parallel lines remains same). In that case the line will have a slope of 2/3.
_________________
Karishma Veritas Prep GMAT Instructor
Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 10229
Location: Pune, India

Re: Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
10 Dec 2018, 00:07
vanam52923 wrote: Here: https://gmatclub.com/forum/aparabolai ... l#p2187473
_________________
Karishma Veritas Prep GMAT Instructor
Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >



Current Student
Joined: 04 Jun 2018
Posts: 155
GMAT 1: 610 Q48 V25 GMAT 2: 690 Q50 V32 GMAT 3: 710 Q50 V36

Re: Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
10 Dec 2018, 01:39
VeritasKarishma wrote: nitesh50 wrote: https://gmatclub.com/forum/inthexycoordinatesystemwhatistheslopeoftheline47203.html
Can you help me understand the concept of equidistant points?
What does this exactly mean? More specifically i cannot understand case 2 mentioned in the discussion.
Case 1) Either a line that is equidistant from the two points must be passing from the the gap between the two points. In this case every point on the line will be equidistant from each of the two given points.
OR
Case 2) The line that is equidistant must be parallel to the line joining the two points (7, 7) and (1, 11). But this case is applicable only when the perpendicular distance of the Line from point is discussed
How is case 2 applicable? If there are 2 points on a line : A and B. We draw a parallel line CD.
In this case not every point in the line CD will be equidistant from A and B.
Looking forward to your opinion.
Regards Nitesh Nitesh, Distance of a point from a line is assumed to be the perpendicular distance. If the line passes through the midpoint of two points, its perpendicular distance from both points will be equal (as explained by walker here: https://gmatclub.com/forum/inthexyco ... ml#p452751) So one way is that the line passes through origin and through the midpoint of PQ. Alternatively, the line could be passing through origin and parallel to PQ. Then perpendicular distance from P to the line and perpendicular distance from Q to the line will be equal (perpendicular distance between two parallel lines remains same). In that case the line will have a slope of 2/3. Hi VeritasKarishmaThank you for the reply. So just a clarification: If 2 points are equidistant from a particular line, then can we say that the perpendicular distance of the points to the line is equal? Regards Nitesh



Senior Manager
Joined: 20 Mar 2018
Posts: 492
Location: Ghana
Concentration: Finance, Real Estate

Re: Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
10 Dec 2018, 01:58
Hello Karishma hope you doing great Please does being solid on only 500600 level questions enable me get to Quant 45? Am now at Quant 30 thus a 15points difference Sent from my iPhone using GMAT Club Forum mobile app



Senior Manager
Joined: 20 Mar 2018
Posts: 492
Location: Ghana
Concentration: Finance, Real Estate

Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
10 Dec 2018, 04:03
Again , If 6 typists all working at the same rate can complete a document in 4hrs ,how many hours will it take 4 typist to complete the same document ? Why is it that when solving this using proportion we use rate in the denominator instead of time like this 6/(1/4)=4/x where x is the rate of 4 typist versus using time in the denominator of the proportions which 6/4 =4/x which gives a wrong ans Sent from my iPhone using GMAT Club Forum mobile app



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 10229
Location: Pune, India

Re: Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
10 Dec 2018, 20:15
nitesh50 wrote: VeritasKarishma wrote: nitesh50 wrote: https://gmatclub.com/forum/inthexycoordinatesystemwhatistheslopeoftheline47203.html
Can you help me understand the concept of equidistant points?
What does this exactly mean? More specifically i cannot understand case 2 mentioned in the discussion.
Case 1) Either a line that is equidistant from the two points must be passing from the the gap between the two points. In this case every point on the line will be equidistant from each of the two given points.
OR
Case 2) The line that is equidistant must be parallel to the line joining the two points (7, 7) and (1, 11). But this case is applicable only when the perpendicular distance of the Line from point is discussed
How is case 2 applicable? If there are 2 points on a line : A and B. We draw a parallel line CD.
In this case not every point in the line CD will be equidistant from A and B.
Looking forward to your opinion.
Regards Nitesh Nitesh, Distance of a point from a line is assumed to be the perpendicular distance. If the line passes through the midpoint of two points, its perpendicular distance from both points will be equal (as explained by walker here: https://gmatclub.com/forum/inthexyco ... ml#p452751) So one way is that the line passes through origin and through the midpoint of PQ. Alternatively, the line could be passing through origin and parallel to PQ. Then perpendicular distance from P to the line and perpendicular distance from Q to the line will be equal (perpendicular distance between two parallel lines remains same). In that case the line will have a slope of 2/3. Hi VeritasKarishmaThank you for the reply. So just a clarification: If 2 points are equidistant from a particular line, then can we say that the perpendicular distance of the points to the line is equal? Regards Nitesh Yes Nitesh, that is correct.
_________________
Karishma Veritas Prep GMAT Instructor
Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 10229
Location: Pune, India

Re: Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
10 Dec 2018, 20:42
Staphyk wrote: Hello Karishma hope you doing great Please does being solid on only 500600 level questions enable me get to Quant 45? Am now at Quant 30 thus a 15points difference Sent from my iPhone using GMAT Club Forum mobile appStaphyk, you will need to be comfortable with 650 level questions too to be in that score range. Note that GMAT will word the questions in an innovative way so even though you may know the concepts, it will take a bit of effort to actually arrive at them. You will need to learn to identify the concept being tested in different scenarios. So it is a good idea to work with 600  700 level questions.
_________________
Karishma Veritas Prep GMAT Instructor
Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 10229
Location: Pune, India

Re: Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
10 Dec 2018, 21:35
Staphyk wrote: Again , If 6 typists all working at the same rate can complete a document in 4hrs ,how many hours will it take 4 typist to complete the same document ? Why is it that when solving this using proportion we use rate in the denominator instead of time like this 6/(1/4)=4/x where x is the rate of 4 typist versus using time in the denominator of the proportions which 6/4 =4/x which gives a wrong ans Sent from my iPhone using GMAT Club Forum mobile appLook, 6 typists complete it in 4 hrs. If you have 4 typists, they will take more than 4 hrs (fewer people to do the work). 4 hrs increases by a fraction. What is that fraction? The one by which the number of people have changed. 4 hrs * (6/4) = 6 hrs Alternatively, if you want to use the workratetime formula, try this: Rate = 6R (because 6 typists work and say rate of each is R) Time = 4 hrs Work = Rate*Time = 4*6R = 24R Now, what happens when we have 4 typists? Rate = 4R Work is same as before i.e. 24R Time = ?? Work = Rate*Time 24R = 4R * Time Time = 6 hrs
_________________
Karishma Veritas Prep GMAT Instructor
Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >



Senior Manager
Joined: 20 Mar 2018
Posts: 492
Location: Ghana
Concentration: Finance, Real Estate

Re: Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
11 Dec 2018, 00:21
VeritasKarishma wrote: Staphyk wrote: Again , If 6 typists all working at the same rate can complete a document in 4hrs ,how many hours will it take 4 typist to complete the same document ? Why is it that when solving this using proportion we use rate in the denominator instead of time like this 6/(1/4)=4/x where x is the rate of 4 typist versus using time in the denominator of the proportions which 6/4 =4/x which gives a wrong ans Sent from my iPhone using GMAT Club Forum mobile appLook, 6 typists complete it in 4 hrs. If you have 4 typists, they will take more than 4 hrs (fewer people to do the work). 4 hrs increases by a fraction. What is that fraction? The one by which the number of people have changed. 4 hrs * (6/4) = 6 hrs Alternatively, if you want to use the workratetime formula, try this: Rate = 6R (because 6 typists work and say rate of each is R) Time = 4 hrs Work = Rate*Time = 4*6R = 24R Now, what happens when we have 4 typists? Rate = 4R Work is same as before i.e. 24R Time = ?? Work = Rate*Time 24R = 4R * Time Time = 6 hrs well explained,Thank you Sent from my iPhone using GMAT Club Forum mobile app



Senior Manager
Joined: 20 Mar 2018
Posts: 492
Location: Ghana
Concentration: Finance, Real Estate

Re: Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
11 Dec 2018, 00:23
VeritasKarishma wrote: Staphyk wrote: Hello Karishma hope you doing great Please does being solid on only 500600 level questions enable me get to Quant 45? Am now at Quant 30 thus a 15points difference Sent from my iPhone using GMAT Club Forum mobile appStaphyk, you will need to be comfortable with 650 level questions too to be in that score range. Note that GMAT will word the questions in an innovative way so even though you may know the concepts, it will take a bit of effort to actually arrive at them. You will need to learn to identify the concept being tested in different scenarios. So it is a good idea to work with 600  700 level questions. very well Karishma ,Thanks for the advice Sent from my iPhone using GMAT Club Forum mobile app



Senior Manager
Joined: 20 Mar 2018
Posts: 492
Location: Ghana
Concentration: Finance, Real Estate

Re: Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
11 Dec 2018, 00:50
used a time consuming way in solving ,help with an efficient way A does a work in 8hours,B does the same work in 16hours and C does it in 12hours. A starts working and is joined by B after 2hours,after 3hours of working together ,A leaves and C joins. How much more time will it take to complete the work if B and C continue to work until it’s over? 600 level? Sent from my iPhone using GMAT Club Forum mobile app



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 10229
Location: Pune, India

Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
Show Tags
12 Dec 2018, 00:16
Staphyk wrote: used a time consuming way in solving ,help with an efficient way A does a work in 8hours,B does the same work in 16hours and C does it in 12hours. A starts working and is joined by B after 2hours,after 3hours of working together ,A leaves and C joins. How much more time will it take to complete the work if B and C continue to work until it’s over? 600 level? Sent from my iPhone using GMAT Club Forum mobile appHey Staphyk, Rate of work of A = 1/8 Rate of work of B = 1/16 Rate of work of C = 1/12 Before B and C start working, A works for 5 hours (2 + 3) and hence does (1/8)*5 = 5/8 of the work. B works for 3 hrs and hence does (1/16)*3 = 3/16 of the work So before B and C start working, 5/8 + 3/16 = 13/16 of the work is already over and just 3/16 is left. Combined rate of B and C = 1/16 + 1/12 = 7/48 Time taken = Work/Rate = (3/16) / (7/48) = 9/7 hrs I would say 650 level.
_________________
Karishma Veritas Prep GMAT Instructor
Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >




Veritas Prep PS Forum Expert  Karishma  Ask Me Anything about Math
[#permalink]
12 Dec 2018, 00:16



Go to page
Previous
1 2 3 4 5 6 7 8 9 10
Next
[ 200 posts ]



