Question

One tap can fills a bath in 12 min and another fills it in 15 min. The waste pipe can empty the bath in 10 min. In what time bath will be filled if both taps are turned on and if the waste pipe has been left open accidentally?
​

Answer 1

Answer:

In 1min 1st tap can fill =1/12

1 min another tap can fill = 1/15

in 1 min waste tap can empty =1/10

$tub \: can \: fill = \frac{1}{12} + \frac{1}{15} - \frac{1}{10} \\ = \frac{5 + 4 - 6}{60} \\ = \frac{3}{60} = \frac{1}{20}$

THEREFORE

IN 20 MIN. BATH TUB WILL FILL