alcohol solute problem

Question

You need a 45% alcohol solution. On hand, you have a 60 mL of a 5% 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

0.05(60) + 0.55x = 0.45(60 + x)

Answer 2

Suppose you add x ml

Total volume = 60 + x

Total alcohol (ml) = 0.05 x 60 + 0.55 x = 3 + 0.55x

So [ 3 + 0.55x ] / [ 60+x] = 0.45

Solve this for x