SOLUTION: a small pump can pump all of the blood out of an average turnip in 30 minutes. a larger pump can pump all of the blood from the same turnip in 20 minutes. If both pumps are hooked

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Question 677555: a small pump can pump all of the blood out of an average turnip in 30 minutes. a larger pump can pump all of the blood from the same turnip in 20 minutes. If both pumps are hooked to the turnip, then how long would it take to get all of the blood out?

I don't know where to start.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Add the rates of pumping to get the rate
pumping together
( blood pumped by small pump ) / ( pumping time ) + ( blood pumped by large pump ) / ( pumping time )
= ( blood pumped with both pumps ) / ( pumping time )
------------------------------
+1%2F30+%2B+1%2F20+=+1%2Ft+
Multiply both sides by +60t+
+2t+%2B+3t+=+60+
+5t+=+60+
+t+=+12+
It will take 12 minutes with both pumps hooked up