Question

How many liters of an 18% alcohol solution must be added to a 10% alcohol solution to get 20L of a 15% alcohol solution

Answer 1

Let x= liters of 18% solution to be added to a 10% solution.

20-x= liters of 10% solution to be mixed with 18% solution.

..

18%(x)+10%(20-x)=15%(20)

.18x+2-.1x=3

..08x=1

x=1/.08=12.5

ans:

12.5 liters of an 18% alcohol solution must be added to a 10% alcohol solution to get 20 L of a 15% acohol solution.

I hope it's helpful!