Question

You need a 75% alcohol solution. On hand, you have a 60 mL of a 55% alcohol mixture. You also have 85% alcohol mixture. How much of the 85% mixture will you need to add to obtain the desired solution?

You will need_____ mL of the 85% solution

Answer 1

60 mL=55% alcohol

?mL=85% alcohol

85×60÷55

=92.727 mL

I think do like this....I'm not sure

Hope this help you

Answer 2

9514 1404 393

Answer:

120 mL

Explanation:

Let x represent the amount of 85% solution needed. Then the total amount of alcohol in the mix is ...

0.55(60) +0.85(x) = 0.75(60 +x)

33 + 0.85x = 45 +0.75x . . . . . . . eliminate parentheses

0.85x = 12 +0.75x . . . . . . . . . .subtract 33

0.10x = 12 . . . . . . . . . . . . . . subtract 0.75x

x = 120 . . . . . . . . . . . . . . multiply by 10

You will need 120 mL of the 85% solution.