Question

50 POINTS!!!!

Leanne can clean a fish tank in 30 minutes. Karl can clean a fish tank in 20 minutes. If they work together, how many minutes does it take them to clean a fish tank?

A)6 minutes
B)10 minutes
C)12 minutes
D)50 minutes

Answer 1

it will take them 12 minutes because 30-20=10 however you add the time of annoyance on therefore making it 12 minutes

Answer 2

C) 12 minutes

Explanation:

Given : Leanne can clean a fish tank in 30 minutes

Karl can clean a fish tank in 20 minutes

To find :

If they work together, how many minutes does it take them to clean a fish tank.

Solution :

Leanne can clean fish tank in 30 minutes = 1 fish tank

Leanne can clean fish tank in 1 minute = 1/30 part of fish tank

Karl can clean fish tank in 20 minutes = 1 fish tank

Karl can clean fish tank in 1 minute = 1/20 part of fish tank

If they work together, they can clean fish tank in 1 minute

=
`(1)/(30) +(1)/(20)`

=
`(5)/(60)`

Thus, If they work together, they can clean fish tank in 1 minute = 5/60 part of fish tank

If they work together, they can clean 5/60 part of fish tank = 1 minute

If they work together, they can clean 1 fish tank

=
`(1)/((5)/(60))`

=
`(60)/(5)`

= 12 minutes

Thus , If they work together it will take 12 minutes to clean a fish tank .