Question

A pharmacist has an 18% alcohol solution and a 40% alcohol solution. How much of each should he mix together to make 10 liters of a 20% alcohol solution?

Answer 1

18x+ 40(10-x)= 20x10
18x +400-40x=200
-22x= -200
22x=200
x=200/22
=100/11
so amount of 18% concentrated alcohol = 100/11 liter
and amount of 40%= 10/11 liter

Answer 2

Answer:

The amount of 18% concentrated alcohol = 9.09 liter

and amount of 40%= 0.90 liter

Step-by-step explanation:

Given : A pharmacist has an 18% alcohol solution and a 40% alcohol solution.  

To find : How much of each should he mix together to make 10 liters of a 20% alcohol solution?

Solution :  

Let x represent the amount of 18% solution,

10-x represents the amount of 40% solution.

So, according to question,

$18x+ 40(10-x)= 20\times 10$  

$18x +400-40x=200$  

$-22x= -200$

$x=\frac{200}{22}$  

$x=\frac{100}{11}$  

$x=9.09$  

Therefore,  

The amount of 18% concentrated alcohol = 9.09 liter

and amount of 40%=10-9.09= 0.90 liter.