# Two drainpipes working together can drain a pool in 12 hours. Working alone, the smaller pipe would take 18 hours longer than the larger pipe to drain the pool. How long would it take the smaller pipe alone to drain the pool?

##### 2 Answers

36hr

#### Explanation:

Time of both working together

Time of small pipe

Let time of large pipe

For pipes in parallel

but time can't be -ve so

so

#### Explanation:

Let

Now, draining rate of smaller pipe

Similarly, draining rate of larger pipe

Given that both the pipes working together can drain the same pool of volume

But

hence, the time taken by the smaller pipe alone to drain the pool is