Question

You need a 40\% alcohol solution. On hand, you have a 150 mL of a 20% alcohol mixture. You also have 55% alcohol mixture. How much of the 55% mixture will you need to add to obtain the desired solution?

Answer 1

You need to add 200 mL of the 55% to obtain the desired solution

Explanation:

x=mixture you need to add

20% * 150 + 55% x = 40%(x + 150)

0.20 * 150 + 0.55x = 0.40(x + 150)

30+0.55x=60+0.40x

0.15x = 30

x=200 mL