A pharmacist wants to make 30 ml of a 40% hydrogen peroxide solution. How many mls of 46% hydrogen peroxide must he mix with 36% hydrogen peroxide to make the desired solution?

Question

A pharmacist wants to make 30 ml of a 40% hydrogen peroxide solution.   How many mls of 46% hydrogen peroxide must he mix with 36% hydrogen peroxide to make the desired solution?

hero · Answer

x  +       y  =       30
.46(x) + .36(y) = .40(30)

hero · Answer

The first equation represents the total amount of solution after combining both mixtures. 
The second equation represents the total amount of hydrogen peroxide present in the solution after combining both mixtures. 

Solving the system yields the values of x and y. The value of x is what you will need to find for this particular problem.

dumbsearch2 · Answer

Right thanks. :) I'm solving the rest, using elimination...

anonymous · Answer

what did you get?

hero · Answer

@alyygirl, Have you tried solving it?

anonymous · Answer

no

hero · Answer

Why not?

anonymous · Answer

where do i start

hero · Answer

Start by isolating y in the first equation.

anonymous · Answer

.46(x) + .36(y) = .40(30)

hero · Answer

The first equation is

x + y = 30

anonymous · Answer

ok

anonymous · Answer

still stuck

hero · Answer

If x + y = 30, then y = 30 - x right?