I need Math Homework help, its word problems, using elimination and substitution?.?

Question

1) In Chemistry class you mix a bottle of 6% hydrogen solution and a bottle of 1% hydrogen solution. You need 50 mL of a 3% hydrogen solution for the experiment. How much of the 6% and 1% solutions do you need?

Please help, and thank you!

Answer 1

Let x be the mL of 6% solution and y be the mL of 1% solution

Since you want to end up with 50mL, x+y=50

Solve for y to use in the substiution: y=50-x

Also, you want

.06*x+.01*y = .03*50

Or, 6x+y=150

Substitute in from the first equation y=50-x

6x + (50-x)=150

5x+50=150

5x=100

x=20

20 mL 6% solution and 30mL 1% solution.

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