Question

Mr. Rhee drives 40 miles at 40 miles per hour and 20 miles at 60 miles per hour, what is Mr.Rhee's average speed, in miles per hour, for the entire trip?
A. 52
B. 50
C. 48
D. 45
E. 42
EXPLAIN!!!

Answer 1

Average speed =
total distance travelled
————------—-----------
By total time taken

Answer 2

D.

First calculate the time from the first speed and distance i.e. 40 miles/h and 40 miles. The time would be 1h.

Then do the same for the second speed and distance. The time would be 1/3 h.

Av speed = total distance/total time
=> 40+20/1+1/3
=>60/4/3
=> 60×3/4
=>45

Hope you understood