Question

In a mixture of 45 liters, the ratio of alcohol and water is 7 ∶ 2. How much quantity of water should be added to make the mixture of 30% water?
1. 5 liters
2. 9 liters
3. 15 liters
4. 21 liters

Answer 1

Correct Answer - Option 1 : 5 liters

Given:

The total quantity of mixture is 60 liters

The ratio of alcohol and water is 7 ∶ 2

Calculation:

Let the added quantity of water be x liters

The final quantity of mixture,

⇒ x + 45

According to the question, we have,

The initial quantity of water,

⇒ 45 × (2/9)

⇒ 10 liters

The final quantity of water,

⇒ x + 10

Now, x liters of water to added to the mixture to make 30% water,

⇒ (x + 10)/(x + 45) × 100 = 30

⇒ (x + 10)/(x + 45) = 3/10

⇒ 10x + 100 = 3x + 135

⇒ 10x - 3x = 135 - 100

⇒ 7x = 35

⇒ x = 5 liters

∴ The added quantity of the water is 5 liters.