Question

What is the average speed required to run a mile (1.6 Km) in 4 minutes?

Answer 1

Step 1: Given data

Distance $D=1.6\hspace{0.17em}k\text{m}$

Time $t=4\hspace{0.17em}\text{min}$

Step 2: Write an expression for average speed:

$v=\frac{D}{t}$

Step 3: Substitute $1.6\hspace{0.17em}k\text{m}$ for $D$ and $4\text{\hspace{0.17em}min}$ for $t$ in the expression of average speed:

$$\begin{gathered} v=\frac{1.6\hspace{0.17em}k\text{m}}{4\hspace{0.17em}\text{min}} \\ =\frac{1.6\left|\text{km}\right|\times {\displaystyle \frac{{10}^3\text{m}}{\left|\text{km}\right|}}}{4\hspace{0.17em}\left|\text{min}\right|\times {\displaystyle \frac{60\hspace{0.17em}\text{sec}}{\left|\text{min}\right|}}} \\ =6.66\frac{\text{m}}{\text{sec}} \end{gathered}$$

Hence, the average speed is $6.66\frac{\text{m}}{\text{sec}}$.