SAT Subject Test Mathematics Level 2

The question requires two formulas. First is the rate formula, which is applied to two different legs
of a journey:

rate × time = distance

B   to  C _____ _____ _______

C   to  B _____ _____ _______

AVERAGE RATE FORMULAS

Second is the average speed formula:

First consider which slots you can fill in Rate × Time = Distance. Notice that you’re given a rate for
the trip from B to C, and you know that the distance going—which you can call d—is the same as the
distance returning. Call the rate from C back to B r. Notice that now is not the time to do much with
the 26.25. One of the most important lessons to learn about the Math 2 test is when to use which
numbers; 26.25 will be important later:

rate × time = distance

B   to  C 21 _____ d

C   to  B r _____ d

Given these values and variables, you can express the time going and the time returning: