# Question #4695d

May 30, 2017

Average speed is defined as the distance travelled by an object in a unit time. The SI unit is $m {s}^{-} 1$ or metre per second.

#### Explanation:

Average speed is given by the formula:-
$v = \frac{x}{t}$ where,
$v$ = speed of the object
x = total distance travelled (in metre)
t = time taken (in second)

In the question, $x = 66$ miles, which is roughly equal to 106216.704 metre.
and for time taken (t) = 4pm - 2.48 pm = 1 hour and 12 minutes = 4320 second.

Hence, by the given relation, the average speed is:-
$v = \frac{106216.704}{4320}$
or $v = 24.58 m {s}^{-} 1$