Question

Charlie runs at the speed of 3 yards per second.
About how many miles per hour does charlie run??

Answer 1

How many seconds are there in an hour?

Answer 2

360?

Answer 3

6.136 mph

Answer 4

thank you

Answer 5

\(1 ~hour \times \dfrac{60~min}{1~hour} \times \dfrac{60~sec}{1~min}\)

\(=1 ~\cancel{hour} \times \dfrac{60~\cancel{min}}{1~\cancel{hour}} \times \dfrac{60~sec}{1~\cancel{min}} = 3600 ~sec\)

1 hour = 3600 sec

Answer 6

He runs 3 yards in 1 second.
There are 3600 seconds in 1 hour, so he runs 3 * 3600 yards in 1 hour
3 * 3600 = 10,800
His speed is 10,800 yd/hr
There are 1760 yards in a mile, so his speed is: 10,800/1760 mph = 6.14 mph

Answer 7

This entire conversion can be done in one calculation:

\(3\dfrac{yd}{sec} \times \dfrac{1~mile}{1760~yd} \times \dfrac{60~sec}{1~min} \times \dfrac{60~min}{1~hour} \)

\(= 6.14 ~mph\)