The cold water faucet of a bathtub can fill the tub in 15 minutes. The drain, when opened, can empty the full tub in 20 minutes.

Question

3 years ago

13

Suppose the tub is empty and the faucet and drain are both opened at the same time. How long will it take to fill the tub?

2 answers:

masya89 [10] · Answer 1 · 2022-07-05T17:47:06+03:00

Answer:

60 minutes

Step-by-step explanation:

faucet takes 15 minutes to fill the tub, so how much of the full tub is added per minute?
$15 minutes=1added/minute\\1minute=\frac{1}{15} added/minute$
drain takes 20 minutes to empty the tub so how much of the full tub is lost per minute?
$20minutes=1lost/minute\\1minute=\frac{1}{20} lost/minute$
How long it takes to fill the tub can be found by how much of it is added per minute minus lost per minute
$totalfilled/minute=added/minute-lost/minute\\=\frac{1}{15} -\frac{1}{20}=\frac{1}{60}$
So one sixtieth of the tub is filled a minute, so that 60 parts of the tub, each taking a minute, that's 60 minutes or 1 hour

pentagon [3] · Answer 2 · 2022-07-05T15:58:40+03:00

5 0

Answer:

10 minutes

Step-by-step explanation:

This is because if u have both the faucet and drain on at the same time, it will fill the tub faster