Question

A jogger runs a mile in 8.92 minutes. 1 mi=1609m; calculate her speed in km/hr

Answer 1

Answer:

$Speed = 3.30 \frac{km}{hr}$

Explanation:

Given

Distance = 1 mile

Time = 8.92 minutes

Required

Calculate Speed in km/hr

Speed is calculated as thus;

$Speed = \frac{Distance}{Time}$

Substitute 1 mile for distance and 8.92 minutes for time

$Speed = \frac{1\ mile}{8.92\ minutes}$

Convert Miles to Kilometres

If

$1\ mile = 1609\ m$;

Then

$1\ mile = \frac{1609\ km}{1000}$

$1\ mile = 1.609\ km$ --- (1)

Convert minutes to hour

$1\ minutes = 0.0167\ hour$

Multiply both sides by 8.92

$8.92 * 1\ minutes = 0.0167\ hour * 8.92$

$8.92 \ minutes = 0.148964\ hour$ ---- (2)

By substituting (1) and (2) in $Speed = \frac{1\ mile}{8.92\ minutes}$, we have

$Speed = \frac{1.609\ km}{0.48694\ hour}$

$Speed = 3.304309 \frac{km}{hr}$

$Speed = 3.30 \frac{km}{hr}$ -- Approximated