Question

how many litres of water should be added to a 30 litre mixture of milk and water of 7 ratio 3 such that the resultant mixture has 40% water in it

Answer 1

Amount of water in mixture is
$30 \times \frac{3}{7 + 3} = 30 \times \frac{3}{10} = 9$
Let water to be added is x. Then,
$\frac{9 + x}{30 + x} \times 100 = 40 \\ \frac{9 + x}{30 + x} = 0.4 \\ 9 + x = 12 + 0.4x \\ 0.6x = 3 \\ x = 5 \: liter$

Answer 2

5 liters of water is added to get 40% solution of water.

Step-by-step explanation:

Since we have given that

Quantity mixture of milk and water = 30 liters

Ratio of milk and water = 7:3

Quantity of milk is given by

$\dfrac{7}{10}\times 30=7\times 3=21\ ltrs$

Quantity of water is given by

$\dfrac{3}{10}\times 30\\\\=3\times 3\\\\=9\ ltrs$

Let the amount of water is added be 'x'.

According to question, we get that

$\dfrac{9+x}{21}=\dfrac{40}{60}\\\\\dfrac{9+x}{21}=\dfrac{2}{3}\\\\3(9+x)=21\times 2\\\\27+3x=42\\\\3x=42-27\\\\3x=15\\\\x=\dfrac{15}{3}\\\\x=5$

Hence, 5 liters of water is added.

# learn more :

In a 729 litres mixture of milk and water, the ratio of milk to water is 7:2. to get a new mixture containing milk and water in the ratio 7:3, the amount of water to be added is

https://brainly.in/question/3809835

Topic: Mixture and allegations