SOLUTION: John can clean a large tank at an aquarium in about 5 hours. When John and Laura work together, they can clean the tank in about 3 hours. About how long would it take Laura to c

Question 977590: John can clean a large tank at an aquarium in about 5 hours. When John and Laura work together, they can clean the tank in about 3 hours.
About how long would it take Laura to clean the tank if she works by herself?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
John's rate of cleaning:
[ 1 tank ] / [ 5 hrs ]
I will call Laura's rate of cleaning:
[ 1 tank ] / [ t hrs ]
Their rate of cleaning working together:
[ 1 tank ] / [ 3 hrs ]
---------------------
Add their rates of cleaning to get their
rate working together:

Multiply both sides by

Working by herself, Laura takes 7 hrs and 30 min
to clean the tank
-------------------
check:

OK

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