Question

Tanya and her brother are racing with their new bikes in the neighborhood. Their block is one mile long. Tanya's average speed is 0.15 mi/s and her brother's is 0.11 mi/s. Who will reach the end of block first, and how much time ahead of the other will they be?

Answer 1

Answer:

Tanya

$2.43\ \text{s}$

Explanation:

$d$ = Distance traveled = 1 mile

$s_t$ = Tanya's average speed = $0.15\ \text{mi/s}$

$s_b$ = Tanya's brother's average speed = $0.11\ \text{mi/s}$

Time taken by Tanya

$t=\dfrac{d}{s_t}\\\Rightarrow t=\dfrac{1}{0.15}\\\Rightarrow t=6.67\ \text{s}$

Time taken by Tanya's brother

$t=\dfrac{d}{s_b}\\\Rightarrow t=\dfrac{1}{0.11}\\\Rightarrow t=9.1\ \text{s}$

So Tanya will reach the end of the block first.

She will reach the end of the block by $9.1-6.67=2.43\ \text{s}$