Question

The distance covered and time taken by Jessi, Lisa, and Mary on a race is given. What is the speed of the person who finished the race first?

Name	Distance (m)	Time (s)
Jessi	$\frac{4}{3}$	$\frac{3}{2}$
Lisa	$\frac{4}{3}$	$\frac{4}{3}$
Mary	$\frac{4}{3}$	$\frac{3}{4}$

• A. $0.93\text{m/s}$
• B. $1\text{m/s}$
• C. $0.89\text{m/s}$
• D. $2\text{m/s}$

Answer 1

The correct option is D $2\text{m/s}$

Name	Distance (m)	Time (s)	Speed (m/s)= $\frac{Distance\left(m\right)}{Time\left(s\right)}$
Jessi	$\frac{4}{3}$	$\frac{3}{2}$	$\frac{4}{3}÷\frac{3}{2}=$ $\frac{4}{3}\times \frac{2}{3}=\frac{8}{9}$ $\Rightarrow 0.89\text{m/s}$
Lisa	$\frac{4}{3}$	$\frac{4}{3}$	$\frac{4}{3}÷\frac{4}{3}=$ $\frac{4}{3}\times \frac{3}{4}=1$ $\Rightarrow 1\text{m/s}$
Mary	$\frac{4}{3}$	$\frac{2}{3}$	$\frac{4}{3}÷\frac{2}{3}=$ $\frac{4}{3}\times \frac{3}{2}=\frac{12}{6}$ $\Rightarrow 2\text{m/s}$

Mary finished the race first as her speed is $2\text{m/s}$ which is greater than $1\text{m/s}$ and $0.89\text{m/s.}$
Hence option C is correct.