50
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

C) 12 minutes

Step-by-step 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

=  

=

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

=

=  

= 12 minutes

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

the reporter's right

step-by-step explanation:

1/4 = .25 / 25%