Problem Solving

lheiannie07 wrote:If Tom goes y miles in x hours, how many miles does he go per minute, in terms of x and y?

A. 60x/y
B. y/60x
C. 60y/x
D. x/60y
E. 60xy

(y miles)/(x hours) * (1 hour)/(60 minutes) = y/(60x) miles per minute.
In the equation above, the units in red CANCEL OUT, leaving the units in blue.

The correct answer is B.

An alternate approach is to PLUG IN.

How many miles does he go per minute?
Let the rate = 2 miles per minute.

Tom goes y miles in x hours.
(2 miles per minute)(60 minutes) = 120 miles per hour, implying that y=120 miles and x=1 hour.

The question stem asks for the number of miles per minute.
Thus, the green value above is our target: 2 miles per minute.
Now plug y=120 and x=1 into the answers to see which yields our target value of 2.
Only B works:
y/(60x) = 120/(60*1) = 2.

The correct answer is B.