McGraw-Hill Education GRE 2019

The primary difference in the two equations is the following:

For distance questions, rate represents distance per unit of time

and the result represents some distance traveled. For work questions,

rate represents output per unit of time and the result represents the

number of units produced (such as widgets, lawns mowed, papers, etc.).

Distance Problems: Rate × Time = Distance

The rate × time = distance formula is almost always the best way to solve distance

equations. In simpler questions, you will be given two components of the formula

and asked to solve for the third.

If a car travels at a constant rate of 50 miles per hour, in how many hours will

the car have traveled 325 miles?

Step 1: Set up the rate × time = distance chart:

rate (mi/hr) × time (hr) = distance (miles)

↓ ↓ ↓

50 × t = 325

Step 2: Solve for t:

50 t = 325

t = 6.5 hours

Unit Conversions

When solving rate questions, be sure that you use the same unit throughout the

question. If the rate is expressed per minute, then you must express time in

minutes, not seconds or hours.

Running at a constant rate, Bob travels 5 miles in 1 hour. If Bob travels for 20

minutes, how many miles does he travel?

Step 1: Set up the r × t = d chart:

rate (mi/hr) × time (hr) = distance (miles)

Bob’s rate is distance/time = 5 miles/1 hour, and his time is 20 minutes. It

might be tempting to simply substitute these values into the original formula,

but this would be incorrect. Why? Because the units do not match up. The

rate is expressed per hour, whereas the time is expressed in minutes. Before

plugging the values into the formula, you should convert the time from 20

minutes to^13 hour.

340 PART 4 ■ MATH REVIEW

04-GRE-Test-2018_313-462.indd 340 12/05/17 12:03 pm