Suppose you invest $3,600 in stocks and bonds paying 4% and 5%, respectively. The interest from both investments after one year is $166. For the following problems, use $x$ for the amount invested in stocks and $y$ for the amount invested in bonds.

a) Write a mathematical expression for the total amount of money invested.
Answer:

b) Write a mathematical expression for the total interest earned.
Answer:

c) How much money was invested in bonds?
Answer: