A girl can ski down a hill five times as fast as she can climb up the same hill. If she can climb up the hill and ski down in a total of 9 minutes, how many minutes does it take her to climb up the hill? Please explain in full detail, and explain any shortcuts. Thank you.

--Taken from Barron's Let's Review: Integrated Algebra

[1] 1.8
[2] 4.5
[3] 7.2
[4] 7.5

Answer = [4] = 7.5

How do you get 7.5?

Question

A girl can ski down a hill five times as fast as she can climb up the same hill. If she can climb up the hill and ski down in a total of 9 minutes, how many minutes does it take her to climb up the hill? Please explain in full detail, and explain any shortcuts. Thank you.

--Taken from Barron's Let's Review: Integrated Algebra

[1] 1.8
[2] 4.5
[3] 7.2
[4] 7.5

Answer = [4] = 7.5

How do you get 7.5?

anonymous · Answer

Define your variables and set up an equation.
D = time down the hill
U = time up the hill
U = 5D

D + U = 9
So
D + 5D = 9

p0sitr0n · Answer

x =time to ski
5x = time to climb
time = 9minutes
x + 5x =9
6x = 9
x =1.5
1.5 *5 = climb = 7.5