Answer:
Step-by-step explanation:
39 cars every 3 hrs.......that means (39/3) = 13 cars every hr
and if its 13 cars every hr....in 7 hrs, there will be (7 * 13) = 91 cars <==
you can either do it that way....the unit rate way...OR
you can set it up as a proportion...
39 cars to 3 hrs = x cars to 7 hrs...
39 / 3 = x / 7....cross multiply
(3)(x)= (39)(7)
3x = 273
x = 273/3
x = 91 <====
either way, u get the correct answer
