Question

Please Help!! 20 pts!!
Use a system of equations to solve this problem.

A chemist currently has two solutions of sodium chloride. One solution has a 5% concentration and the other has a 25% concentration. The chemist needs to make 10 L of a 10% sodium chloride solution.
Let x = the amount of 5% solution.
Let y = the amount of 25% solution.
 
How much of each solution does the chemist need to make?

Answer 1

I just did this

0.05x+0.25y=0.1(10)

x+y=10
y=10-x

0.05x+0.25(10-x)=0.1(10)
0.05x+2.5-0.25x=1
2.5-0.2x=1
minus 2.5 both sides
-0.2x=-1.5
divide both sides by -0.2
x=7.5

sub back

y=10-x
y=10-7.5
y=2.5



x=7.5
y=2.5

needs 7.5L of the 5%
needs 2.5L of the 25%