Question

Part 1: Suppose you receive $200 for a graduation present, and you deposit it in a savings account that doesn't accrue interest. Each week thereafter, you add $15 to the account. Write an equation to represent this function.

Part 2: How many weeks will it take before you have at least $500 in your account?
Part 3: Suppose you receive $200 for a graduation present, and you spend $15 a week of that money on Friday night movie tickets. Write an equation to represent this function.
Part 4: If you were to graph the functions from parts 1 and 3, how would they look on a coordinate plane?

Answer 1

The equation to represent this function is y = 200 + 15x. It will take at least 20 weeks to have $500 in the account. The graph of the first function would be a line with a positive slope starting at $200.

Step-by-step explanation:

Part 1: The equation to represent this function is y = 200 + 15x, where y represents the total amount of money in the savings account and x represents the number of weeks.

Part 2: To find out how many weeks it will take to have at least $500 in the account, we can set up an inequality. $200 + 15x ≥ $500. Solving this inequality, we subtract $200 from both sides and then divide both sides by 15. The result is x ≥ 20, so it will take at least 20 weeks to have $500 in the account.

Part 3: The equation to represent this function is y = 200 - 15x, where y represents the total amount of money left after spending on movie tickets and x represents the number of weeks.

Part 4: If we were to graph the functions from parts 1 and 3, the graph of the first function would be a line with a positive slope starting at $200, while the graph of the second function would be a line with a negative slope starting at $200.