(Please help me--) Monica built a porch that contained 2 different colors of bricks to create a pattern. She purchased the red bricks for $7 each and the gray bricks for $4 each. Write a system to find out how many red bricks Monica purchased if she spent $193 on 40 bricks?
a. What is the system that models this situation?
Equation #1:
Equation #2:
b. How many red bricks did Monica purchase?