One pump can fill a tank with oil in 4 hours. A second pump can fill the same tank in 3 hours. If both pumps are used at the same time, how long will they take to fill the tank?
First pump can fill the tank in 4 hours. So, In 1 hour it ill fill
Same way second pump will fill in 1 hour =
If both pumps are used at the same time, then in 1 hour they will fill
Therefore tank will be full =