If speed varies inversely as the time it takes to drive and Kris takes 5 hours driving at 55 mph, what speed will Martin need to drive if he wants to take 5 1/2 hours?
A)52.4 mph
B)51.5 mph
C)50 mph
D)60.5 mph
To solve this problem, we can use the formula for inverse variation:
Speed1 x Time1 = Speed2 x Time2
Given that Kris takes 5 hours driving at 55 mph, we can write it as:
55 x 5 = Speed2 x 5 1/2
275 = Speed2 x 5.5
Speed2 = 275 / 5.5
Speed2 = 50
Therefore, Martin will need to drive at 50 mph if he wants to take 5 1/2 hours.
So, the answer is:
C) 50 mph