Answer:
C, D
Explanation:
Given a list of distances and times, you want to know which rates are correctly computed.
Speed
Speed is the ratio of distance to time. The various distances and times given can be used to compute the associated speed.
A. 32 mi in 2/3 h
The speed is ...
(32 mi)/(2/3 h) = (32)(3/2) mi/h = 48 mi/h ≠ 45 mph
B. 48 mi in 3/4 h
The speed is ...
(48 mi)/(3/4 h) = (48)(4/3) mi/h = 64 mi/h ≠ 60 mph
C. 70 mi in 1 1/4 h
The speed is ...
(70 mi)/(5/4 h) = (70)(4/5) mi/h = 56 mi/h
D. 75 mi in 1 1/2 h
The speed is ...
(75 mi)/(3/2 h) = (75)(2/3) mi/h = 50 mi/h
E. 90 mi in 1 3/4 h
The speed is ...
(90 mi)/(7/4 h) = (90)(4/7) mi/h = 51 3/7 mi/h ≠ 51 mph