Question 758597
Hi,

You have some good idea :)

For this problem,

You need to find 2 equations for a linear system.

Let call x to be the amount of 50% acid and y to be the amount of 25% acid

We know the total is 20 L, thus the first equation is x + y = 20

Another equation would be about the mixture: 0.5x + 0.25y = 0.4(20) = 8

So you have the system of 2 linear equations:

x + y = 20
0.5x + 0.25y = 8

You can solve for x and y ( which is the amount of 25% acid)

If you need some more assistance, please email me.

Thank you!