To help you sharpen your math skills and hit your target score of Q49-51, we are sending you 4 math questions (2 DS, 2 PS) and solutions regularly.
These questions are the types of questions appearing in GMAT exam frequently.
Please Click the link for solutions.
[Math Revolution] Practice “Math Questions of the Day�
This topic has expert replies
- Max@Math Revolution
- Elite Legendary Member
- Posts: 3991
- Joined: Fri Jul 24, 2015 2:28 am
- Location: Las Vegas, USA
- Thanked: 19 times
- Followed by:37 members
Math Revolution
The World's Most "Complete" GMAT Math Course!
Score an excellent Q49-51 just like 70% of our students.
[Free] Full on-demand course (7 days) - 100 hours of video lessons, 490 lesson topics, and 2,000 questions.
[Course] Starting $79 for on-demand and $60 for tutoring per hour and $390 only for Live Online.
Email to : [email protected]
For question #1, why is the answer C and not B?
A77A is a multiple of 9 so that means A77A is divisble by 9
=> A+7+7+A is divisible by 9
=> 2A+14 is divisible by 9
=> 2(A+7) is divisible by 9
=> 2 is not divisible by 9 so (A+7) has to be divisible by 9
=> Range for A is from 0-9 and only 2 can be the valid solution for (A+7) to be divisible by 9. This is an unique answer just as you have mentioned in the solution. So, why is statement 2 alone not sufficient?
A77A is a multiple of 9 so that means A77A is divisble by 9
=> A+7+7+A is divisible by 9
=> 2A+14 is divisible by 9
=> 2(A+7) is divisible by 9
=> 2 is not divisible by 9 so (A+7) has to be divisible by 9
=> Range for A is from 0-9 and only 2 can be the valid solution for (A+7) to be divisible by 9. This is an unique answer just as you have mentioned in the solution. So, why is statement 2 alone not sufficient?