Mamadou and Brianna work at a dry cleaners ironing shirts. Mamadou can iron 15 shirts per hour, and Brianna can iron 25 shirts per hour. Mamadou worked 2 more hours than Brianna and they ironed 230 shirts between them. Write a system of equations that could be used to determine the number of hours Mamadou worked and the number of hours Brianna worked. Define the variables that you use to write the system.​