Question

Robert borrowed $750 from his parents to make some repairs on his car. He promised to repay the loan by giving his parents at least $67 from his paycheck each week. Assuming Robert sticks to his promise, which of the following is not a possible scenario for the amount of debt Robert has remaining?

After 5 weeks, Robert is $150 in debt.

After 6 weeks, Robert is $200 in debt.

After 7 weeks, Robert is $250 in debt.

After 8 weeks, Robert is $300 in debt <- my answer

@MrNood @Astrophysics

Answer 1

@paki

Answer 2

Consider the minimum payment
Week interest paid loan (at most) (x = total loan - interest paid)
1 67 750 - 67 = 683
2 67 x 2 = 134 750 - 134 = 616
3 67 x 3 = 201 750 - 201 = 549
4 67 x 4 = 268 750 - 268 = 482
5 67 x 5 = 335 750 - 335 = 415
6 67 x 6 = 402 750 - 402 = 345
7 67 x 7 = 469 750 - 469 = 281
8 67 x 8 = 536 750 - 536 = 214

The amount of the loan can be less than x as he may pay more than 67 in any weeks. However, it cannot be greater than x as he keeps his promise to pay the minimum amount of 67. Can you get the answer now?

Answer 3

I'm not sure, would it be 8 weeks?

Answer 4

@sprattfield

Answer 5

Yes

Answer 6

Wait, why 8 weeks though?

Answer 7

@sprattfield

Answer 8

@AloneS Can you double check my answer?

Answer 9

So what was your answer?