Having the same capacity 9 taps fill up a water tank in

Having the same capacity 9 taps fill up a water tank in 20 minutes. How many taps of the same capacity are required to fill up the same water tank in 15 minutes ?

Here , M₁ = 9 taps , D₁ = 20 minutes , M₂ = ? , D₂ = 15 minutes
Using the given formula ,
M₁ D₁ = M₂ D₂
⇒ 9 × 20 = M₂ × 15

⇒ M₂ =	9 × 20	= 12 pipes
	15

Note : Same relation as men and days is applicable