Question

The production line where you work can assemble 5 amplifiers every 30 minutes. At this rate, which correctly calculates the number of hours it takes to assemble 230 amplifiers?

A) divide 230 by 30 and then multiply by 5
B) divide 230 by 30 and then multiply by 2
C) divide 230 by 5 and then multiply by 2
D) divide 230 by 5 and then multiply by 0.5

Answer 1

If the production line where you work can assemble 5 amplifiers every 30 minutes, then 1 amplifier can be assembled in
`(30)/(5) =6` minutes.

To assemble 230 amplifiers you need
`230\cdot 6=1380` minutes that is 23 hours.

Then the correct choice is D, because
`(230)/(5) \cdot 0.5=23`.