# Kiran creating an alcohol solution by mixing two different alcohol solutions of 15% and 20% respectively. If the resulting mixture has 18% alcohol con

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Kiran creating an alcohol solution by mixing two different alcohol solutions of 15% and 20% respectively. If the resulting mixture has 18% alcohol content, what is the ratio of the volume of alcohol solutions used?
1. 1 : 3
2.  2 : 3
3. 5 : 2
4. 2 : 1

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Correct Answer - Option 2 :  2 : 3

Calculation:

Let volume of alcohol solutions are Vand  Vrespectively.

⇒ Volume of alcohol in the resulting mixture = 15% of V+ 20% of V2

⇒ ((15/100) × V1) + ((20/100) × V2)

⇒ (15V1+ 20V)/100

which is also equal to 18% of (V+ V2).

⇒ (15V1+ 20V)/100 = (18 × (V+ V2))/100

2V= 3V1

The ratio of volume is 2 : 3 .

If a mixture of Q1 quantity C1% content is mixing with Q2 quantity C2% mixture, and the concentration of the new mixture is Cnew% , then the following equation can be used

C1% of Q1 + C2% of Q2 = Cnew% of (Q1 + Q2)

⇒ C1Q1 + C2Q2 = Cnew(Q1 + Q2)