# One tube fills the pool in 15 hours. How many hours and minutes will it take to fill the pool with 4 same type tubes?

Jun 26, 2018

#### Answer:

color(blue)(3 " hrs " 45 " minutes"

#### Explanation:

This is a case of inverse variation:

For inverse variation, we have:

$y \propto \frac{k}{x} ^ n$

Where $\boldsymbol{k}$ is the constant of variation.

We need to find this constant $\boldsymbol{k}$

Let $y$ be the number of hours taken. Let $x$ be the number of tubes.

$y = 15$ and $x = 1$

$\therefore$

$15 = \frac{k}{1}$

$k = 15$

Now if we have 4 tubes:

$x = 4$

$y = \frac{15}{4} = 3 \frac{3}{4}$hrs

or:

$3 \text{ hrs " 45 " minutes}$