Mark's house is 90 miles away from New York. You travel 15 miles on city streets, and then 75 miles on the highway.

a. your average speed is 25 miles per hour in the city and 60 miles per hour on the highway. Use the formula time=distance/rate. How much time will you spend traveling on city streets? How much time will you spend on the highway?

He travels 15 miles on city streets at 25 mph

time = distance/rate = 15/25 or .6 hrs
= 36 minutes

do the same for the highway situation.