Math Problem #3

Question

You need a 65% alcohol solution. On hand, you have a 130 mL of a 15% alcohol mixture. You also have 75% alcohol mixture. How much of the 75% mixture will you need to add to obtain the desired solution?

Answer 1

15(130) + 75(x) = 65(130+x)

1950 + 75x = 8450 + 65x

10x = 8450-1950 = 6500

x = 650 ml of 75% solution

130+x = 780 ml of 65% solution

75% is much closer to 65% than to 15%. It's five times closer

650 = 5 times 130