Question

It takes 12 hours for a single hose to fill a large vat. When a second hose is added, the vat can be filled in 4 hours.

Answer 1

The answer is 3 because you divide 12 and 4

Answer 2

Its 6 hours.

I should probably explain it, the reason for this is mainly just by dividing the fact that adding the other hose takes away 8 hours of work we can deduce that the amount of water it can put out can do it 2 times faster than the normal hose so the answer is 6