Question

which speed is the fastest: A. 18 feet in 20 minutes B. 90 feet in 2.5 hours X. 20 feet in 1.5 hours D. 3 2/3 feet in 15 minutes
Show your work

Answer 1

answer is c. 
so you are going to divide minutes over feet to get feet per minute.
20/18=0.9 ft per min
150/90=1.67 ft per min
90/20=4.5 ft per min
15/3 and two-thirds= 4.09

Answer 2

Convert each item to feet/minute:-

A  = 18/20  = 0.9 ft/min
B =  90 / (2.5 * 60)  = 90 / 150 = 0.6 ft/min
C = 20 / 90 = 0.22 ft/min
D = 3 2/3  / 15 =  11/3 * 1/15 =  0.24 ft/min

So the answer is A.