Problema Solution
A sink can be filled from the faucet in 5 minutes. It takes only 3 minutes to empty the sink when the drain is open. If the sink is full and both the faucet and the drain are open, how long will it take to empty the sink?
Answer provided by our tutors
the rate of the faucet is 1/5 sinks per min
the rate of the drain is 1/3 sinks per min
let t = the time in min needed for the sink to empty when both the faucet and the drain are open
1 + t/5 - t/3 = 0
by solving we find
t = 7.5 min
click here to see the step by step solution of the equation
it will take 7.5 min for the sink to empty.