Milly has $83.50 in her savings account. she deposits $15 every week. her mother also deposits $10 into the account every time milly washes the car. her savings account balance can be shown with the following expression: 10c + 15w + 83.50 part a: identify a coefficient, a variable, and a constant in this expression. (3 points) part b: if milly saves for 15 weeks and washes the car 4 times, how much will she have in her account? show your work to receive full credit. (4 points) part c: if milly’s mom deposited $20 after each car wash, would the coefficient, variable, or constant in the expression change? why? (3 points)