All questions of Mock Tests for GRE Exam

P and Q take 4 hours to complete a task. P, Q, and R take 2 hours to complete the task.
a)
Quantity A is greater
b)
Quantity B is greater
c)
The two quantities are equal
d)
Cannot be determined
Correct answer is option 'A'. Can you explain this answer?

Talent Skill Learning answered

Step 1: Frame Equations for information given in the Question Stem
Let the time taken by P alone, Q alone, and R alone be p, q, and r hours respectively.
So, in 1 hour P will complete 1/p
So, in 1 hour Q will complete 1/q
So, in 1 hour R will complete 1/r
Information 1: P and Q complete the task in 4 hours.
Therefore, P and Q will complete 1/4 th of the task in 1 hour.
Fraction of work done by P and Q in 1 hour is

P, Q, and R complete the task in 2 hours
Therefore, P, Q, and R will complete 1/2 the task in 1 hour.
Fraction of work done by P, Q, and R in 1 hour is

Step 2: Solve Equations (1) and (2)
Subtract equation (1) from equation (2)

So, r = 4

R alone takes 4 hours. to complete the task.
It is given that, P and Q together take 4 hours.
Therefore, each of P and Q alone will take more than 4 hours.

Step 3: The comparison
Quantity A: Time taken by P alone to complete the task. We know P takes more than 4 hours
Quantity B: Time taken by R alone to complete the task. R takes 4 hours to complete the task.
Quantity A > Quantity B

Choice A is the correct answer for this GRE Quantitative Comparison Question

View Answers

Join for Free

Chapter doubts & questions for Mock Tests - 2 Months Preparation for GRE General Test 2025 is part of GRE exam preparation. The chapters have been prepared according to the GRE exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for GRE 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.

Chapter doubts & questions of Mock Tests - 2 Months Preparation for GRE General Test in English & Hindi are available as part of GRE exam. Download more important topics, notes, lectures and mock test series for GRE Exam by signing up for free.