Question 757722
Hi, 

For this kind of problem, you must create a linear system of 2 equations to solve for each type.

Let x be amount of 40% solution
----y--------------25% solution

The first equation you will have is the total of 2 solutions. You know that the total is 100 L: x + y = 100

The second equation is the mixture between them to create a new solution:

0.4x + 0.25y = (0.36)(100) = 36


So you will have a system:

x + y = 100
0.4x + 0.25y = 36

Solve the system then you will have the amount of each solution.

Good luck! John