We can start by using the formula for inverse variation: t = k/r, where k is a constant of proportionality. We can solve for k by plugging in the given values for t and r:
12 = k/60
k = 720
Now we can use this value of k to find the time required to drive the same distance at 85 miles per hour:
t = 720/85
t ≈ 8.47 hours
Therefore, the answer is (D) about 8.47 hours.
The time, t, required to drive a certain distance varies inversely with the speed, r. If it takes 12 hours to drive the distance at 60 miles per hour, how long will it take to drive the same distance at 85 miles per hour?
A. about 7.08 hours
B. about 5.00 hours
C. about 1.42 hours
D. about 8.47 hours
3 answers
or, simply
x(85) = 12(60)
x = 720/85= 8.47 or appr 8.5 hours
x(85) = 12(60)
x = 720/85= 8.47 or appr 8.5 hours
Yes, that is another way to solve the problem using the property of inverse variation.