Question

When Amy roller-skates, she moves 110 yards per minute. What is her speed in miles per hour? Round your answer to the nearest hundredth. (Hint: 1 yd= 3 ft; 5280 ft = 1 yd.; 60 min= 1 hr)

Answer 1

Speed of Amy is 3.75 miles per hour.

Explanation:

We have, speed of Amy = 110 yards per minute

This means, she covers 110 yards of distance in 1 minute.

Now, to convert the speed of Amy into miles per hour, we will first convert the distance from yards into miles and then convert time from minutes to hour.

We know that,

1 yard = 3 feet

∴ 110 yards = 3 × 110 feet = 330 feet

Now, we also know that,

5280 feet = 1 mile

∴ 1 feet =
`(1)/(5280)` miles

So, 330 feet =
`(1)/(5280)*330` =
`(1)/(16)` miles

∴ 110 yards = 330 feet =
`(1)/(16)` miles

Now, 60 min = 1 hr

∴ 1 min =
`(1)/(60)` hrs

So, 110 yards =
`(1)/(16)` miles and 1 min =
`(1)/(60)` hr

So, we can say that, Amy covers a distance of
`(1)/(16)` miles in

`(1)/(60)` hr.

We know that,

`speed=(distance)/(time)`

`speed=(((1)/(16)) miles)/(((1)/(60))hr)`

`speed=(60)/(16) miles/hr = 3.75 miles/hr`

Therefore, the speed of Amy in miles/hr is 3.75 miles/hr.