DISTANCE, RATE, AND TIME
Yet another classic situation with a standard approach is the distance-rate-and-time question.
Example 7 is an interesting variation.
AVOID THE SPEED TRAP
When a problem asks for average rate or average speed, don’t just average the given rates or
speeds. It’s not that simple. Use the Average Rate formula.Example 7Here’s another great example of how structuring the data in a question is often the most important
step in the solution; once you’ve imposed order on the situation described in a question stem,
actually getting to the answer is often merely a matter of putting the right numbers in the right
places, and calculating with care.
Kayla drove from Bayside to Chatham at a constant speed of 21 miles per hour and then returned
along the same route from Chatham to Bayside. If her average speed for the entire journey was
26.25 miles per hour, at what average speed, in miles per hour, did Kayla return from Chatham
to Bayside?1.
(A) 28
(B) 31
(C) 31.5
(D) 35
(E) It cannot be determined from the information given.