Here is the problem:

Jane is asked to make a 37 milliliter solution of 12% HCL. However, only 8% and 15% HCL is available in the lab. How many milliliters of each solution should be use?

I started out by setting up the variables like this, but then I don't know what to do afterwards. Here is how I set up the variables.

Let x=number of ml of 8% HCl

y=number of ml of 15% HCL

Any help on how to solve this would be great appreciated!