Question

Joshua has $1 and begins saving $2 each week towards buying a new game. At the same time that Joshua begins saving, Adelyn has $4 and begins saving $1 per week for new art supplies.

Part A: Which week will they have the same amount of money?


Part B: How much do they have at that time?


Part C: How did the graph help you answer Part A and B?

Answer 1

Part A

Set linear equations for both amounts:

• Joshua saves 1 + 2x and Adelyn saves 4 + x, where x - number of weeks.

Since the amounts are same, set them equal:

• 1 + 2x = 4 + x
• 2x - x = 4 - 1
• x = 3

After 3 weeks.

Part B

After 3 weeks they will have:

• 1 + 2*3 = 7 or
• 4 + 3 = 7

The amount saved is $7.

Part C

The intersection of two lines has coordinates of (3, 7) which indicate the number of weeks and saved amount.