Question

8 pipes are required to fill a tank in 1 hour 20
minutes. How long will it take if only 5 pipes of
the same type is used?​

Answer 1

$\bf \ QUESTION$

8 pipes are required to fill a tank in 1 hour 20

minutes. How long will it take if only 5 pipes of

the same type is used?

$\bf ANSWER$

⊙1 hr and 20 mins will be 80mins⊙

So 8 pipes take 80 mins to fill a tank.

The more number of pipes, the less time it takes to fill a tank. In this case, the tank is a constant as there is only 1 tank needed to be filled.

y=k/x

let y be time

let x be number of pipes

80=k/8

k= 80(8)

k= 640

y=640/5

y= 128 mins

y= 2hr 8mins

Answer 2

Question :-

• 8 pipes are required to fill a tank in 1 hour 20minutes. How long will it take if only 5 pipes ofthe same type is used?

Given :-

• 8 pipes are required to fill a tank in 1hour 20minutes.

To find :-

• How long will it take if only 5 pipes of the same type is used?

Solution :-

Let the desired time to fill the tank be x minutes.

In 80 mins a tank is filled by 8 pipes

Lesser the number of pipes more will be the time required by it to fill the tank.

So, this is a case of inverse proportion.

$Hence, 80×8= x×5$

$</p><p>\implies\dfrac{80 \times 8}{5} =\sf x$

$\implies \dfrac{640}{5} =\sf x$

$\implies \sf x = \dfrac{ \cancel{640} }{ \cancel{5}}$

$\implies\sf x = 128$

Thus, the time is taken to fill the tank by 5 pipes is 128 minutes or 2 hour 8 minutes.