Help pls (1 Viewer)

[nrumble42]

Tranh borrowed $20 000 on 1 January 2008. He agreed that on January 1 in each succeeding year he would pay back $3000 and add to the debt 6% p.a interest on the amount owing during the year just completed. Find:
a) the amount still owing immediately after 1 January 2013
b) the number of years necessary to pay off the debt

 

[OkDen]

a)$8,838.56
b)9 years

Can someone check my answer plz?

 

[Mahan1]

a)$8,838.56
b)9 years

Can someone check my answer plz?

the answers are correct, as far as I can tell, but this is a proper proof:
after 1 year:
owed money=
after 2 years:
owed money=
.
.
.
.
after n years:
owed money =
you can use geometric sum formula to further simplify
for a) let n =5
for b) the hassle free method is trial and error you just have to notice n=8 we still owe some amount of money but after n=9 we are cleared.
9 years is the answer