Question

A bicyclist covers 60 miles between 2 pm and 6 pm. What was his average speed?
A) 15 mph
B) 30 mph
C) 45 mph
D) 60 mph
E) Not enough information is given to be able to say

Answer 1

Hint: The average speed of a body is given by the total distance travelled by the body to the total time taken during its journey. Here it is given that the total distance covered is 60 miles and the total time taken by it is 2 pm to 6 pm i.e. 4 hours.

Complete step by step answer:
It is given in the question that total distance travelled is 60 miles and total time taken is 4 hours, so the average speed is given by the expression
${V_{av}} = {D \over T}$
Where, D= total distance and T= total time
So,
$\eqalign{
  & {V_{av}} = {{60} \over 4} \cr
  & {V_{av}} = 15mph \cr} $

Hence the average speed is 15 mph.

The average speed is calculated for a body when it covers a certain distance at various speeds at various intervals of time. The average speed gives the mean value of speed during its whole journey.

Note: Here the formula for normal speed and average speed is the same because its varying distance travelled in different intervals of time are not given. Only the total distance and time is available. In that case the formula for both the expressions becomes the same.