Ms. lieber takes 4 hours to drive 210 miles from her home to yosemite National Park. if Miss Lieber's average speed for the first two hours is 60 miles per hour, find her average speed for the last 2 hours

This is correlation between distance-time-speed that we will use in answering

d = vt

t = d/v

v = d/t

d stands for distance, v stands for velocity/speed, t stands for time

First, we should count the distance she took for the first two hours

d = vt

d = (60) (2)

d = 120

For the first two hours, she took 120 miles

Second, calculate the distance for the next two hours

d = total distance - first distance

d = 210 - 120

d = 90

The remaining distance is 90 miles

Third, calculate the speed for the next 2 hours

s = d/t

s = 90/2

s = 45

The speed for the last two hours is 45 miles per hour

Answer: 45 miles/hour

60 x 2 = 120 miles for the 2 hours,

210 - 120 = 90

AVG speed for the last 2 hours is 45 MPH