Question

28 pumps can empty a reservoir in 18 hours. In how many hours can 42 such pumps do the
work?​

Answer 1

The time required for empty a reservoir =

Answer 2

$\bf{\underline{\underline{\red{Question:-}}}}$

• 28 pumps can empty a reservoir in 18 hours. In how many hours can 42 such pumps do the work ?

$\bf{\underline{\underline{\red{Given:-}}}}$

• 28 pumps can empty a reservoir in 18 hours.

$\bf{\underline{\underline{\red{Find:-}}}}$

• how many hours 42 pumps will take to do that work ?

$\bf{\underline{\underline{\red{Solution:-}}}}$

Let,

• The time taken by 42 pump be X

$\sf → Pumps \: \: \: \: \:\:\: \: \: \: \:\:Time$

→ 28 ⠀⠀⠀⠀⠀⠀⠀ 18

→ 42 ⠀⠀⠀⠀⠀⠀⠀ x

We know,

• As the number of pumps increase the time taken by pump will decrease.

So,

• the given relation it inverse relation

$\sf → \dfrac{28}{42}=\dfrac{18}{x}$

$\sf → x = \dfrac{28}{42}×18$

$\sf → x = \dfrac{28}{7}×3$

$\sf → x = 4×3$

$\sf → x = 12$

$\bf{\underline{\underline{\red{Hence:-}}}}$

• 42 pumps takes 12 hours to do same work.