Problema Solution
a gasoline-powered pump can drain Betty's entire swimming pool in 24 hours. an electric pump can drain the entire pool in 36 hours. after the electric pump was operating for one hour, the gasoline pump was started and both pumps were used until the pool was drained. how long did the gasoline pump operate?
Answer provided by our tutors
Let 't' be the time that the gasoline pump operated.
gasoline-powered pump drains entire swimming pool in 24 hours in 1 hour it will drain 1/24 parts of the pool
electric pump drains entire swimming pool in 36 hours in 1 hour it will drain 1/36 parts of the pool
Amount of work done by pump in t hours = t/(speed of the pump) thus we have
t/24 + (t+1)/36 = 1
By simplifying and solving the above equation we get a result
t = 14 hours
The gasoline pump operated 14 hours.