Tap A can fill an empty swimming pool in 10 h . Tap B can fill it in 15 h . How much time will the two taps take to fill the empty pool together?

Correct option is C

​$$\text{Time taken by tap } (A + B) \text{ to fill the swimming pool} \\= \frac{30}{(3+2)} = \frac{30}{5} = 6 \text{ hours}$$​​