I NEED HELP PLEASE, THANKS! :)

Aswimming pool has an input pump for filling the pool and an output pump for emptying the pool. the input pump can fill the pool in 3 hours, and the output pump can drain the pool in 5 hours. as you go to bed, the pool is full, but a neighbor’s kid turns on the output pump. at midnight, you awake to find the pool half empty. immediately, you turn on the input pump, but you are sleepy and forget to turn off the output pump. at what time will the pool become full?

You have 3 boxes, one "strawberries"; one "mentos" and one "mixed".but you know that all the labels are in incorrect order .how do you know witch is witch?

The perimeter of a movie screen is 54 meters. the screen is 18 meters wide. how tall is it?