Question

(01.02 HC) Marla has $95.50 in her savings account. She deposits $5 every week. Her mother also deposits $20 into the account every time Marla washes the car. Her savings account balance can be shown with the following expression: 20c + 5w + 95.50 Part A: Identify a coefficient, a variable, and a constant in this expression. (3 points) Part B: If Marla saves for 20 weeks and washes the car 5 times, how much will she have in her account? Show your work to receive full credit. (4 points) Part C: If Marla’s mom deposited $10 after each car wash, would the coefficient, variable, or constant in the expression change? Why?

Answer 1

Part A:

Variable is a symbol for a number we don't know yet. It is usually a letter like x or y but can be any letter. 
Example: 6z means 6 times z, and "z" is the variable.

Hence, the variables are c and w. [ Choose any one for your answer ]

Coefficient is any number used to multiply a variable.
Example: 6z means 6 times z, and "z" is a variable, so 6 is a coefficient.

Hence, the coefficients are 20 and 5. [Choose any one for your answer]

A constant is a fixed value which does not change regardless of the variables entered.

Hence, the constant is 95.50

Part B:

Weeks saved (w) = 20

Cars washed (c) = 5

20c + 5w + 95.50 = (20 * 5) + (5 * 20) + 95.50 = 100 + 100 + 95.50 = 295.50

Hence, Marla will have $ 295.50 in her account.

Part C:

In 20c + 5w + 95.50, Marla's mom deposits $ 20 after every car wash.

If Marla's mom deposits only $ 10 after every car wash, then, the new equation would be : 10c + 5w + 95.50

Hence, the coefficient will change from 20 to 10.