Question

in a mixture of 45 litres the ratio of milk to water is 13:2 how much water must be added to this mixture to make the ratio of milk to water 3:1

Answer 1

Amount of milk = 45 × 13/15 = 39 L
Amount of water = 45 - 39 = 6.

Let water to be added is x.
Then,
$\frac{39}{6 + x} = \frac{3}{1} \\ 18 + 3x = 39 \\ x = 7$
Water to be added is 7 L

Answer 2

Answer:

7 liters of water must be added to this mixture to make the ratio of milk to water 3:1

Step-by-step explanation:

Total amount of mixture = 45 liters

The ratio of milk to water is 13:2

So, Amount of milk = $\frac{13}{15} \times 45$

                               = $39$

Amount of water = 45-39 = 6 liters

Now let x be the amount of water must be added to this mixture to make the ratio of milk to water 3:1

So, $\frac{39}{6+x}=\frac{3}{1}$

$39=18+3x$

$39-18=3x$

$21=3x$

$\frac{21}{3}=x$

$7=x$

Hence 7 liters of water must be added to this mixture to make the ratio of milk to water 3:1