Hayley borrowed $1,854.she agreed to repay them in equal installments over the next 18 months. how much does hayley still owe her parents after year?

It would be 618 dollars after one year because you have to find the ratio for how much money per month she has to pay so her debt would be paid after 18 months. 
You would do: 1,854 divided by 18 which equals 103

Then, multiply by 12 much would be 1,236 

Then, subtract 1,854 and 1,236 which will equal 618

Thus your answer is 618 dollars 

Yes you do, so £1973.09 - £1473.50 = £499.59 so tim overpaid £499.59 .hope this ; )