Last visit was: 15 Jul 2024, 13:23 It is currently 15 Jul 2024, 13:23
Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
SORT BY:
Date
Tags:
Show Tags
Hide Tags
Math Expert
Joined: 02 Sep 2009
Posts: 94354
Own Kudos [?]: 641105 [1]
Given Kudos: 85011
Send PM
VP
VP
Joined: 09 Mar 2016
Posts: 1143
Own Kudos [?]: 1025 [1]
Given Kudos: 3851
Send PM
Director
Director
Joined: 16 Sep 2016
Status:It always seems impossible until it's done.
Posts: 641
Own Kudos [?]: 2134 [2]
Given Kudos: 174
GMAT 1: 740 Q50 V40
GMAT 2: 770 Q51 V42
Send PM
VP
VP
Joined: 09 Mar 2016
Posts: 1143
Own Kudos [?]: 1025 [0]
Given Kudos: 3851
Send PM
In the XY-plane, the line with equation ax + by + c = 0, where abc ≠ 0 [#permalink]
Gladiator59 wrote:
Hello dave13,

You have solved it almost perfectly in statement 1. ( though you missed a minus sign). However, solving to find b is not required, just knowing that a unique value can be found is sufficient as it is a DS
ALWAYS remember this to save time.

For statement 2. -c/b = 5/2

So all we know is the ratio of c and b -> we cannot predict the exact value of b based on this. As b could be 2 or 4 or 8 ... any number based on what c is as long as the ratio is the same ( -5/2)

Hope you got why the answer should be (A) and statement (2) is not sufficient.

Best,
Gladi


dave13 wrote:
Hello Gladi Gladiator59 any idea?
have a good day! :)



thanks Gladiator59 for nice explanation :) i understand i dont need to solve DS questions like PS, but i am still learning, so I need to see logical solutions in DS as well at this learning stage :)
Director
Director
Joined: 16 Sep 2016
Status:It always seems impossible until it's done.
Posts: 641
Own Kudos [?]: 2134 [1]
Given Kudos: 174
GMAT 1: 740 Q50 V40
GMAT 2: 770 Q51 V42
Send PM
Re: In the XY-plane, the line with equation ax + by + c = 0, where abc ≠ 0 [#permalink]
dave13 wrote:

Statement One: a = 2, and slope −3

the slope = \(-\frac{a}{b}\) = -3

\(-a = -3b\)

\(-3b= -2\)

\(b = -\frac{2}{3}\) Sufficient



Statement Two: c = 5/2

y intercept is \(-\frac{c}{b}\)

But we dont know anything of B. it is indeed insufficient :grin:

IMO: A

p.s.
Gladiator59 :) thank you ! :) Edited my solution. can you please check if all is correct. i got confused reagrding minus sign i missed in ST ONE.


Again in the last step of statement calculation, you have missed removing the minus sign. So b = 2/3.

Makes sense to solve DS like PS to get more practice - but don't make a habit of it. :-)
Regards,
Gladi
GMAT Club Bot
Re: In the XY-plane, the line with equation ax + by + c = 0, where abc ≠ 0 [#permalink]
Moderator:
Math Expert
94354 posts