SOLUTION: Pump a can fill a tank in 12 minutes Pump b can fill a tank in 20 minutes How long to fill a tank with pump a and b together

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Question 830518: Pump a can fill a tank in 12 minutes
Pump b can fill a tank in 20 minutes
How long to fill a tank with pump a and b together
Answer by tommyt3rd(5050) About Me  (Show Source):
You can put this solution on YOUR website!
together they are
1%2FT=1%2Fa%2B1%2Fb%0D%0A
%0D%0A1%2FT=1%2F12%2B1%2F20=2%2F15%0D%0A
%0D%0AT=15%2F2%0D%0A
so 7 minutes, 30 seconds