Question

Caitlin has saved $120 from her summer job. As the school year starts, Caitlin is going to deposit another $5 each week from her allowance. Is her account balance proportional to the number of weeks of deposits?

Answer 1

No

Explanation:

week 1: balance = 120 +5(1) = $125

week 2: balance = 120 +5(2) = $130

week 3: balance = 120 + 5(3) = $135

week 4: balance = 120 +5(4) = $140

divided the weeks to see if it's proportional

week 1: 125 / 1 = 125

week 2: 130 / 2 = 65

week 3: 135 / 3 = 45

week 4: 140 / 4 = 35

the differences between weeks

Week 1 & 2 : 125 - 65 = 60

Week 2 & 3: 65 -45 - 20

Week 3 & 4: 45 -35 = 10

their not the same so no

Answer 2

Yes, Caitlin's account balance is proportional to the number of weeks of deposits. As she deposits $5 each week, her account balance will increase by $5 for every week that passes.