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02 Nov 2021, 08:45
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A
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
5%
(low)
Question Stats:
86% (01:05) correct
14%
(01:30)
wrong
based on 169
sessions
History
Date
Time
Result
Not Attempted Yet
\((\frac{1}{p})^ 2 − (\frac{1}{p})(\frac{1}{q}) =\)
(A) \(\frac{q−p}{p^2q}\)
(B) \(\frac{p−q}{p^2q}\)
(C) \(\frac{q−p}{q^2p}\)
(D) \(\frac{q−p}{p^2−pq}\)
(E) \(\frac{1}{p^2−pq}\)
(A) \(\frac{q−p}{p^2q}\)
(B) \(\frac{p−q}{p^2q}\)
(C) \(\frac{q−p}{q^2p}\)
(D) \(\frac{q−p}{p^2−pq}\)
(E) \(\frac{1}{p^2−pq}\)
02 Nov 2021, 10:03
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Bunuel
Given: \((\frac{1}{p})^ 2 − (\frac{1}{p})(\frac{1}{q}) \)
Rewrite as: \(\frac{1}{p^2} − \frac{1}{pq}\)
Rewrite fractions with common denominators: \(\frac{q}{p^2q} − \frac{p}{p^2q}\)
Combine numerators: \(\frac{q-p}{p^2q} \)
Answer: A
02 Nov 2021, 10:20
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I will narrate my thought process as I went through this problem:
This looks like very messy algebra involving the computation of LCMs in variables. I hate algebra so I will just use plugging numbers with two different values for p and q. I used p = 2 and q =3. I needed the computation from the question stem to match that in the answer choices.
Plugging would not be too cumbersome since D and E are unlikely to be answers (guess at this point since those involve subtraction which is not a normal operation when doing LCM computation) so that only gives 3 probable choices which you would do the computation on.
I went with testing A and B first over C since they have the same denominator, so I am thinking that the GMAT test writers are placing these two to be the likely tiebreakers. This also helps justify the plugging in numbers strategy at this point. No turning back, plugging numbers it is.
I went with it and started with A. Lo and behold, it yielded the expected answer so my answer is A.
This looks like very messy algebra involving the computation of LCMs in variables. I hate algebra so I will just use plugging numbers with two different values for p and q. I used p = 2 and q =3. I needed the computation from the question stem to match that in the answer choices.
Plugging would not be too cumbersome since D and E are unlikely to be answers (guess at this point since those involve subtraction which is not a normal operation when doing LCM computation) so that only gives 3 probable choices which you would do the computation on.
I went with testing A and B first over C since they have the same denominator, so I am thinking that the GMAT test writers are placing these two to be the likely tiebreakers. This also helps justify the plugging in numbers strategy at this point. No turning back, plugging numbers it is.
I went with it and started with A. Lo and behold, it yielded the expected answer so my answer is A.
