Answer:
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
= \(\frac{1}{30} +\frac{1}{20}\)
= \(\frac{5}{60}\)
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
= \(\frac{1}{\frac{5}{60}}\)
= \(\frac{60}{5}\)
= 12 minutes
Thus , If they work together it will take 12 minutes to clean a fish tank .
