Question

Ari walked 2 3/4 miles at a constant speed of 2 1/2 miles per hour. Beth walked 1 3/4 miles at a constant speed of 1 1/4 miles per hour. Cindy walked for 1 hour and 21 minutes at a constant speed of 1 1/8 miles per hour. List the three people in order of the times they spent walking from least to greatest.

Answer 1

Time Ari Spent

$speed = \frac{distance \: covered}{time \: taken}$

$2 \frac{1}{2} mph = \frac{ 2\frac{3}{4} }{time}$

$time= \frac{ 2\frac{3}{4} h }{ 2 \frac{1}{2} mph }$

$time= \frac{ \frac{11}{4} }{ \frac{5}{2} }hours$

$time= \frac{11}{10} hours$

$time =1 \frac{1}{10} hours = 1.1 \: hours$

Time Beth spent

$1 \frac{1}{4} mph = \frac{ 1\frac{3}{4} }{time}$

$time = \frac{ 1\frac{3}{4} }{1 \frac{1}{4} mph}$

$time = \frac{ \frac{7}{4} }{ \frac{5}{4}} hours$

$time = \frac{7}{5} hours$

$time = 1 \frac{2}{5} hours = 1.4 \: hours$

Time Cindy Spent


We convert Cindy's time to hours.

$1 \: hour \: 21 \: minutes \: = 1 \frac{21}{60} hours = 1 \frac{7}{20} hours = 1.35hours$

In order of time spent,

Ari, Cindy, Beth