Question

we have a bathtub that fills with water in 6 minutes if we pull the plug bath empties in 10 minutes

Answer 1

This is a question on ratios and proportion.

It takes the tap:

6 minutes to fill

10 minutes to empty.

In 1 minute :

1/6 is filled and 1/10 is emptied.

Water retained :

1/6 - 1/10 = 5/30 - 3/30 = 2/30

= 1/15

Time taken to fill the tank when both taps are open :

Reciprocal of 1/15

This equals 15 minutes

Answer 2

It takes the tap:

6 minutes to fill

10 minutes to empty.

So in 1 minute :

1/6 is filled and 1/10 is emptied.

Water retained in the chamber :

1/6 - 1/10 = 5/30 - 3/30 = 2/30

= 1/15

Time taken to fill the tank when both taps are open is equal to reciprocal of 1/15

This equals 15 minutes.