Question

Two chemicals X and Y are to be mixed together to achieve a 16ml solution that is 7.4% water. Chemical x is 5% water and Y is 9% water. How much Y should be used in the mix?

Answer 1

9.6 mL

Explanation:

If x is mL of chemical X, and y is mL of chemical Y, then:

x + y = 16

0.05x + 0.09y = 0.074(16)

Solve the system of equations using substitution.

0.05(16 − y) + 0.09y = 0.074(16)

0.8 − 0.05y + 0.09y = 1.184

0.04y = 0.384

y = 9.6

You need 9.6 mL of Y.