[Math Revolution GMAT math practice question]
2^p/2^q=?
1) p = q + 2
2) pq=8
2^p/2^q=?
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
Timer
00:00
Your Answer
A
B
C
D
E
Global Stats
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]
GMAT/MBA Expert
- Brent@GMATPrepNow
- GMAT Instructor
- Posts: 16207
- Joined: Mon Dec 08, 2008 6:26 pm
- Location: Vancouver, BC
- Thanked: 5254 times
- Followed by:1268 members
- GMAT Score:770
Timer
00:00
Your Answer
A
B
C
D
E
Global Stats
Target question: What is the value of (2^p)/(2^q) ?Max@Math Revolution wrote:[Math Revolution GMAT math practice question]
What is the value of (2^p)/(2^q) ?
1) p = q + 2
2) pq = 8
This is a good candidate for rephrasing the target question.
Aside: Here's a video with tips on rephrasing the target question: https://www.gmatprepnow.com/module/gmat- ... cy?id=1100
Take: (2^p)/(2^q)
Apply the Quotient law to get: 2^(p - q)
This means (2^p)/(2^q) = 2^(p - q)
So, in order to evaluate (2^p)/(2^q), all we need to do is determine the value of p - q
So,......
REPHRASED target question: What is the value of p-q ?
Statement 1: p = q + 2
Subtract q from both sides to get: p - q = 2
So, the answer to the target question is p - q = 2
Since we can answer the REPHRASED target question with certainty, statement 1 is SUFFICIENT
Statement 2: pq = 8
There are several values of x and y that satisfy statement 2. Here are two:
Case a: p = 8 and q = 1. In this case, the answer to the REPHRASED target question is p - q = 7
Case b: p = 4 and q = 2. In this case, the answer to the REPHRASED target question is p - q = 2
Since we cannot answer the REPHRASED target question with certainty, statement 2 is NOT SUFFICIENT
Answer: A
Cheers,
Brent
- 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
Timer
00:00
Your Answer
A
B
C
D
E
Global Stats
=>
Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution.
The first step of the VA (Variable Approach) method is to modify the original condition and the question. We then recheck the question.
Modifying the question:
What is the value of 2^p/2^q= 2^{p-q}?
So, we need to be able to find the value of p-q.
Thus, condition 1), which is equivalent to p - q = 2, is sufficient.
Condition 2):
If p =4 and q = 2, then 2^p/2^q= 2^{p-q} = 2^2 = 4.
If p =8 and q = 1, then 2^p/2^q= 2^{p-q} = 2^7 = 128.
Since we don't have a unique solution, condition 2) is not sufficient.
Therefore, A is the answer.
Answer: A
Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution.
The first step of the VA (Variable Approach) method is to modify the original condition and the question. We then recheck the question.
Modifying the question:
What is the value of 2^p/2^q= 2^{p-q}?
So, we need to be able to find the value of p-q.
Thus, condition 1), which is equivalent to p - q = 2, is sufficient.
Condition 2):
If p =4 and q = 2, then 2^p/2^q= 2^{p-q} = 2^2 = 4.
If p =8 and q = 1, then 2^p/2^q= 2^{p-q} = 2^7 = 128.
Since we don't have a unique solution, condition 2) is not sufficient.
Therefore, A is the answer.
Answer: A
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]