Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 43785

If the length of Wanda's telephone call was rounded up to [#permalink]
Show Tags
14 Jun 2012, 02:09
Question Stats:
74% (01:11) correct 26% (00:52) wrong based on 1129 sessions
HideShow timer Statistics



Math Expert
Joined: 02 Sep 2009
Posts: 43785

Re: If the length of Wanda's telephone call was rounded up to [#permalink]
Show Tags
14 Jun 2012, 02:10
1
This post received KUDOS
Expert's post
5
This post was BOOKMARKED
SOLUTIONIf the length of Wanda's telephone call was rounded up to the nearest whole minute by her telephone company, then Wanda was charged for how many minutes for her telephone call?(1) The total charge for Wanda's telephone call was $6.50. Clearly insufficient since we don't know the cost per minute of call. (2) Wanda was charged $0.50 more for the first minute of the telephone call than for each minute after the first. So, if the first minute costs \($(x+0.5)\) then each succeeding minute costs \($x\). Still not sufficient. (1)+(2) We have that \((x+0.5)+x(n1)=6.5\) > \(xn=6\), where \(n\) is the number of minutes. We have one equation and two unknowns, hence we cannot solve for \(n\). Not sufficient. Answer: E.
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Kellogg MMM ThreadMaster
Joined: 28 Mar 2012
Posts: 319
Location: India
GMAT 1: 640 Q50 V26 GMAT 2: 660 Q50 V28 GMAT 3: 730 Q50 V38

Re: If the length of Wanda's telephone call was rounded up to [#permalink]
Show Tags
14 Jun 2012, 04:27
1
This post received KUDOS
Hi,
Difficulty level: 600
To find the time duration of Wanda's call,
Using (1), Total charge for the call = $6.5, we neither know the number of minutes nor call charges. Insufficient.
Using (2), Wanda was charged $0.50 more for the first minute of the telephone call than for each minute after the first. x+0.5 for first minute, for second minute x, & so on, for the whole call total charges would be nx+0.5 (n = number of minutes) or nx+0.5 = 6.5 or nx = 6 (1*6 or 6*1 or 2*3 or 3*2) thus, (n,x) = (1,6) or (6,1) or .... which means, for 1 min $6 can be charged. or for 6 mins $1 can be charged. Insufficient.
Answer is (E),
Regards,



Manager
Joined: 07 Sep 2011
Posts: 62
Location: United States
Concentration: Strategy, International Business
WE: General Management (Real Estate)

Re: If the length of Wanda's telephone call was rounded up to [#permalink]
Show Tags
16 Jun 2012, 03:40
2
This post received KUDOS
1
This post was BOOKMARKED
Difficulty level: 650
We have to find the duration of the call say N minutes.
1. Statement 1: It gives information about the cost of total call however we do not know per minute cost hence can not calculate the minutes.
2. Statement 2: We know that the cost of first minute was higher by 0.50 cents however we do not know the cost of subsequent minutes. Secondly, we cant calculate the duration of the call with this information.
Put together, we know the total cost and also know that cost of first minute was higher by 0.50. If for example cost of subsequent minutes were 50 cents, the total duration would have been 12 minutes. Reduce the cost of call made after first minute, the duration will change.
Hence answer is E



Director
Status: Final Countdown
Joined: 17 Mar 2010
Posts: 534
Location: India
GPA: 3.82
WE: Account Management (Retail Banking)

Re: If the length of Wanda's telephone call was rounded up to [#permalink]
Show Tags
23 Jul 2012, 06:29
Total call minutes=Total call cost/Cost per min (i) m=6.5/c insufficient (ii)m={(c+0.5)+c*(m1)}/c insufficient combining; m can't be calculated so, (E)
_________________
" Make more efforts " Press Kudos if you liked my post



Math Expert
Joined: 02 Sep 2009
Posts: 43785

Re: If the length of Wanda's telephone call was rounded up to [#permalink]
Show Tags
20 Aug 2013, 02:51



Manager
Joined: 26 Mar 2017
Posts: 160

If the length of Wanda's telephone call was rounded up to [#permalink]
Show Tags
29 Apr 2017, 01:26
Bunuel wrote: SOLUTION
If the length of Wanda's telephone call was rounded up to the nearest whole minute by her telephone company, then Wanda was charged for how many minutes for her telephone call?
(1) The total charge for Wanda's telephone call was $6.50. Clearly insufficient since we don't know the cost per minute of call.
(2) Wanda was charged $0.50 more for the first minute of the telephone call than for each minute after the first. So, if the first minute costs \($(x+0.5)\) then each succeeding minute costs \($x\). Still not sufficient.
(1)+(2) We have that \((x+0.5)+x(n1)=6.5\) > \(xn=6\), where \(n\) is the number of minutes. We have one equation and two unknowns, hence we cannot solve for \(n\). Not sufficient.
Answer: E. I've just an important question (at least imo). I solved the problem correctly but it took me a too much time. I also ended up with an equation with two unknowns. But since they said "telephone call was rounded up to the nearest whole minute" i was a bit suspicious and tried out numbers in order to make sure that there is more than one solution. Often in DF we make the argument that we can't solve an equation with two unknown, but in fact sometimes we can infer that theres only one plausible solutions (For Instance in the following problem) A certain fruit stand sold apples for $0.70 each and bananas for $0.50 each. If a customer purchased both apples and bananas from the stand for a total of $6.30, what total number of apples and bananas did the customer purchase ? So my question is just, when we can make the argument that we are dealing with an equation with two unknowns and when we can't make this argument. hope its clear Thank you !
_________________
I hate long and complicated explanations!



Intern
Joined: 22 Mar 2017
Posts: 3

Re: If the length of Wanda's telephone call was rounded up to [#permalink]
Show Tags
22 Aug 2017, 05:31
Bunuel wrote: If the length of Wanda's telephone call was rounded up to the nearest whole minute by her telephone company, then Wanda was charged for how many minutes for her telephone call? (1) The total charge for Wanda's telephone call was $6.50. (2) Wanda was charged $0.50 more for the first minute of the telephone call than for each minute after the first. Diagnostic Test Question: 27 Page: 25 Difficulty: 650 Hi Brunel, I have one question. Since xn = 6 and to get 6 (x,n) can be (1,6) or (6,1) or (3,2) or (2,3). Because if the length of the call was less than a minute, then I think the total charge for the call would be $6.50. And out of all the possibilities listed above, only (2,3) satisfies the equation 1(x+0.50)+(x1)n = 6.50. So Answer C. Tell me where did I go wrong?



Math Expert
Joined: 02 Sep 2009
Posts: 43785

Re: If the length of Wanda's telephone call was rounded up to [#permalink]
Show Tags
22 Aug 2017, 06:44
shrutiwali wrote: Bunuel wrote: If the length of Wanda's telephone call was rounded up to the nearest whole minute by her telephone company, then Wanda was charged for how many minutes for her telephone call? (1) The total charge for Wanda's telephone call was $6.50. (2) Wanda was charged $0.50 more for the first minute of the telephone call than for each minute after the first. Diagnostic Test Question: 27 Page: 25 Difficulty: 650 Hi Brunel, I have one question. Since xn = 6 and to get 6 (x,n) can be (1,6) or (6,1) or (3,2) or (2,3). Because if the length of the call was less than a minute, then I think the total charge for the call would be $6.50. And out of all the possibilities listed above, only (2,3) satisfies the equation 1(x+0.50)+(x1)n = 6.50. So Answer C. Tell me where did I go wrong? There are other cases possible: n = 6 minutes and x = 1 > the cost of the first minute = $1.5 and the cost each of the remaining 5 minutes = $1 > total = $6.50 n = 3 minutes and x = 2 > the cost of the first minute = $2.5 and the cost each of the remaining 2 minutes = $2 > total = $6.50 n = 2 minutes and x = 3 > the cost of the first minute = $3.5 and the cost of the remaining 1 minute = $3 > total = $6.50
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



EMPOWERgmat Instructor
Status: GMAT Assassin/CoFounder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 11018
Location: United States (CA)
GRE 1: 340 Q170 V170

Re: If the length of Wanda's telephone call was rounded up to [#permalink]
Show Tags
12 Dec 2017, 10:51
Hi All, We're told that Wanda's telephone call was rounded up to the nearest whole minute by her telephone company. We're asked for the number of minutes that she was charged for her telephone call. We can answer this question with a bit of logic and TESTing VALUES. 1) The total charge for Wanda's telephone call was $6.50. With Fact 1, we know the total cost of the call, but we don't know what rate Wanda was charged per minute. Fact 1 is INSUFFICIENT 2) Wanda was charged $0.50 more for the first minute of the telephone call than for each minute after the first. Fact 2 tells us the DIFFERENCE in the rates, but does not tells us the rates themselves nor the length of the call Fact 2 is INSUFFICIENT Combined, we know The total cost of the call was $6.50 The first minute cost $0.50 more than each of the additional minutes IF.... 1st minute = $1.00 and each addl. minute = $0.50, then the call would have been 12 minutes 1st minute = $1.50 and each addl. minute = $1.00, then the call would have been 6 minutes Combined, INSUFFICIENT Final Answer: GMAT assassins aren't born, they're made, Rich
_________________
760+: Learn What GMAT Assassins Do to Score at the Highest Levels Contact Rich at: Rich.C@empowergmat.com
Rich Cohen
CoFounder & GMAT Assassin
Special Offer: Save $75 + GMAT Club Tests Free
Official GMAT Exam Packs + 70 Pt. Improvement Guarantee www.empowergmat.com/
***********************Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!***********************




Re: If the length of Wanda's telephone call was rounded up to
[#permalink]
12 Dec 2017, 10:51






