Question

A pharmacist needs to strengthen a 15% alcohol solution
to one of 32% alcohol.How much pure alcohol should be added to 800 ml of 15% solution?

Answer 1

Add 200ml of pure alcohol

Answer 2

Answer:

Required amount is 160 ml.

Step-by-step explanation:

Given : A pharmacist needs to strengthen a 15% alcohol solution to one of 32% alcohol.

To find : How much pure alcohol should be added to 800 ml of 15% solution?

Solution :

Let x be the amount of pure alcohol.

15% alcohol solution    

Amount of active ingredient = 0.15x ml

Pure alcohol is 800 ml added

So, Amount of active is 800-x ml

32% solution of alcohol:

Amount of active is $0.32\times 800 = 256 ml$

The required equation is,

$0.15x + 800-x = 256$

 $0.85x =544$

 $x =640$

Amount of pure alcohol needed for the solution is

800-x =800-640= 160 ml

Therefore, Required amount is 160 ml.