Answer:
last option is correct
Step-by-step explanation:

D = rt, Distances Equal
72t = 90(t-1)
90 = 18t
90/18 = t = 5hr
second car catch up to the first in 4hrs
Answer:
c
Step-by-step explanation:
Answer:
18 ft. tall
Step-by-step explanation:
This is because if 1 in. equals 2 ft. and the wall of the model were 9 ft. tall you would multiply 9 in. by 2 ft. and get 18 ft.