Question

A worker in an assembly line takes 2 hours to produce 120 parts. At that rate how many parts can she produce in 9 hours?

Answer 1

2/120 = 9/x

solve for x

Answer 2

i dont get it

Answer 3

cross multiply to get

2/120 = 9/x

2*x = 120*9

2x = 1080

x = ???

Answer 4

540

Answer 5

correct

Answer 6

In general, find the unit rate: amount done in 1 unit of time. Then multiply by the amount of time.

Here we have 120 parts in 2 hours, so the unit rate is 120 parts / 2 hours = 60 parts/hour. Now multiply that by 9 hours and you get 60 parts / hour * 9 hours = 540 parts.