Question

Beyonce is trying to make a cocktail by mixing Pepsi and Mango juice in a vessel. The quantity of mixture is 32 liters. The ratio of Pepsi to Juice is 7 ∶ 1. If 3 liters juice is more added to the mixture, the ratio of Pepsi to juice changes to new ratio. If she want to change back the new ratio to original one. Then find how much Pepsi is to be added?   
1. 21 L
2. 12 L
3. 13 L
4. 31 L

Answer 1

Correct Answer - Option 1 : 21 L

Given∶

Quantity of mixture = 32

Ratio of Pepsi to juice = 7 ∶ 1

3 L extra juice is added to the mixture.

Formula Used∶

 

Simple concept of ratios.

a ∶ b can be written as ax and bx where x is a positive integer. 

Calculation∶

Initial ratio of Pepsi to Juice = 7 ∶ 1 

Let the quantity of juice be x and Pepsi be 7x.

According to question,

⇒ 7x + x = 32

⇒ 8x = 32

⇒ x = 4

In the original mixture,

Quantity of Pepsi = 7x = 7 × 4 = 28 L

Quantity of Juice = x = 4 L

After 3 L of juice is added to the mixture,

Quantity of  Pepsi = 28 L

Quantity of juice = 4 + 3 = 7 L

New ratio of Pepsi and juice = 28 ∶ 7

Let x L of Pepsi be extra added.

So, New quantity of Pepsi/New quantity of juice = Original ratio

 ⇒ (28 + x) / 7 = 7/1

⇒  28 + x = 49

⇒  x = 49 - 28 = 21

∴ 21 liters of Pepsi be added.