# Shari drove for 90 miles in the city. When she got on the highway, she increased her speed by 20 mph and drove for 130 miles. If Shari drove a total of 4 hours, how fast did she drive in the city?

##### 1 Answer

Dec 11, 2016

45 mph

#### Explanation:

Let's call her speed in the city

Speed is miles per hour -speed=

Rearranged

Time =

So in the city the time is

After the time is

The total time is 4 hours

So

The common denominator is

So

Divide through by 4

Factorise

So

Check it out 90 miles at 45mph plus 130 miles at 65 mph is 4 hours