Mixture Problem Mathematics

Question

A scientist needs 20ml of a 18% acid solution for an experiment. The lab has available a 30% solution. How many ml of the 10% solution should the scientist mix to make the 18% solution?

Answer 1

30-18 =12

18-10 = 8

12/8 = 3/2

1.5 times as much 10% is needed as 30% to get 18%

12 ml of 10% mixed with 8 ml of 30% yield 20 ml of 18%

check the answers

.10(12)+ .30(8) = 1.2+2.4 = 3.6

= .18(20) = 3.6