Rough estimate: The amount coming out of the 2 pipes is about 300 L/min so if each pipe has the same width, then the rate will be about 150 L/min for each pipe. But one pipe's rate is 50 L/min more than the other, so we expect the answers to be around 125 L/min and 175 L/min.
Solution: Let x be the rate of the slower pipe (in L/min).
The rate of the faster pipe will be
`(x + 50)` L/min.
Together they release: x + (x + 50) = 330
So `2x + 50 = 330`
`2x = 280`
`x = 140`
So the drainage rates of the 2 pipes are `140` L/min and `190` L/min.
[This is close to our earlier estimate. Together they give a rate of `330` L/min and they differ by 50 L/min, so we can be confident our answer is correct.]