McGraw-Hill Education GRE 2019

A tank that is half full is filled with gas at a constant rate of 3 liters per minute.

QUANTITY A QUANTITY B

6. A B C D

Working at the same constant rate, 8 machines

can produce 7 computers in 6 hours.

QUANTITY A QUANTITY B

7. A B C D

Exercise Answers

Discrete Quantitative Questions

1. 169 To determine average speed, use the rate formula: r = dt. You are told that
   the distance for the trip is 45 miles, so the formula now reads r =^45 t. You must
   determine the time spent on the trip. To do so, determine the time for the first
   part of the trip and for the second part, and add up these quantities. You are
   told that the time for the first part of the trip is 40 minutes. For the second
   part of the trip, use the formula: t = dr. The distance for the second part of the
   trip is 30 miles. The rate for the second part of the trip is twice the rate for the
   first part. The rate for the first part is^1540 =^38 , so the rate for the second part of
   the trip is 2 ×^38 =^34. Plug these values into the formula for time and arrive at
   t = 30/(^34 ) = 40. The time for the second part of the trip is also 40 minutes, so
   the time for the entire trip is 80 minutes. Now you can plug this value into the
   rate formula: r = dt =^4580. Reduce and arrive at 169.


2. D Boris’s rate for the entire 24-mile race is 6 miles per hour. Plugging these
   values into the r × t = d formula, you arrive at
   6 t = 24
   t = 4
   Thus the whole race took him 4 hours. If it took him 1.8 hours to run the first
   part of the race, then the second part of the race took him 4 – 1.8 = 2.2 hours.


3. A To get the combined rate of the two hoses, you should add up their rates.
   Rate = worktime, so the rate of the first hose is 101 and the rate of the second hose is
   1
   15. Add up these rates:

1

10 +

1

15 =

5

30 =

1

6. Since the pool is already half full, the

work that the two hoses need to do is only^12. Now plug these values into the

r × t = w formula.

The number of minutes

it will take to fill the

tank completely.

30

The number of

machines needed to

produce 21 computers in

18 hours

8

350 PART 4 ■ MATH REVIEW

04-GRE-Test-2018_313-462.indd 350 12/05/17 12:04 pm