Question

Each week, Rosario drives to an ice skating rink that is 120 miles away. The round-trip takes 2.75 hours. If he averages 55 miles per hour on his way to the rink, which equation can be used to find x, the number of miles per hour he averages on his way home?

A.) 120/55 + 120/x = 2.75
B.) 120/55 x 120/x = 2.75
C.) 120(55) + 120x = 2.75
D.) 120(55) x 120x = 2.75

Answer 1

A

120/55 will give you the time it takes him to get there. If you subtract that value from both sides, you'd have:

120/x = # hours left

From there you could easily solve his average speed home.

Answer 2

`(120)/(55)+ (120)/(x)= 2.75`

Explanation:

Given : Rosario drives to an ice skating rink that is 120 miles away. The round-trip takes 2.75 hours.

To Find : If he averages 55 miles per hour on his way to the rink, which equation can be used to find x, the number of miles per hour he averages on his way home?

Solution:

Distance traveled on going = 120 miles

Speed on going = 55 miles/hour

`Time = (Distance)/(Speed)`

`Time = (120)/(55)`

Distance traveled on returning = 120 miles

Let the speed on returning be x

So,
`Time = (Distance)/(Speed)`

`Time = (120)/(x)`

We are given that Total time of round trip = 2.75 hours

So,
`(120)/(55)+ (120)/(x)= 2.75`

Hence Option A is true .

So, equation can be used to find x, the number of miles per hour he averages on his way home is
`(120)/(55)+ (120)/(x)= 2.75`