Solve |z| > (1/2)

this is the whole question and i just dont get the steps

A.) 18 feet in 20 minutes 
B.) 90 feet in 2.5 hours
C.) 20 yards in 1.5 hours
D.) 3.6 yards in 15 minutes

A) 18/20=0.9 ft per min
B) 2.5 hours equals 150 minutes .                    90/150=0.6 ft per min
C) 20 yds = 60 ft       1.5 hours  = 90 minutes   60/90≈0.67 ft per min
D) 3.6 yds = 10.8 ft    10.8/15=0.72

Therefore the fastest would be 0.6 ft per minute therefore, choice
B) 90 feet in 2.5 hours