Question

A pharmacist wants to make 36ml of a 65% hydrogen peroxide solution. how many pls of 75% hydrogen peroxide must he mix with 57% hydrogen peroxide to make the desired solution?

Answer 1

16 mls of the 75% solution and 20 mls of the 0.57% solution.

Explanation:

Set up a system of equations:

Let x = volume of 75% solution and y be volume of 57% solution

0.75x + 0.57y = 36*0.65

0.75x + 0.57y = 23.4.......(1)

x + y = 36.........(2)

From equation (2):

y = 36 - x

Substituting this into equation(1):

0.75x + (0.57(36 - x) = 23.4

0.75x + 20.52 - 0.57x = 23.4

0.18x = 23.40 - 20.52 = 2.88

x = 2.88/0.18

x = 16

so from equation (2): y = 36-16 = 20.