Question

The Sanchez family drove 132 miles in 3 hours before lunch. Then they drove 240 miles in 5 hours after lunch.

What was their average speed for the day?

A.
46 mi/h

B.
54 mi/h

C.
54.5 mi/h

D.
46.5 mi/h

Answer 1

The formula for speed is the total distance traveled over time. We shall calculate the 2 speeds individually- before and after lunch. Afterwhich, we shall add them together and divide by 2 to get the average.
Before lunch s = 132 mi / 3 hr = 44 mi/hr
After lunch s = 240 mi / 5 hr = 48 mi/hr

Ave s= 48 + 44 / 2
Ave s= 46 mi/hr

Therefore the correct answer is A.