Question

Fred washes a car in 6 minutes, Carl washes a car in 8 minutes. If they wash a car together then how long will it take?

Answer 1

Based on the problem Carl will complete...

1/6 of the job per minute.

Fred will complete 1/8 of the job per minute.

Together they will complete... 1/6+1/8 of the job per minute.

That would be 7/24.

How long will that take?

1/(7/24)=24/7=3 3/7

It will take 3 and 3/7 minutes to finish washing the car.

Answer 2

3.5 minutes.

Explanation:

If Fred can wash 1/6 of a car in 1 minute and Carl can was 1/8 of a car in a minute as well then together in 1 minute it would be:

= 1/6 + 1/8

= 4/24 + 3/24

= 7/24

=
`3(3)/(7\\)`

= 3.429

So we have:

≈ 3.5 min

I hope this helps!