Answer: 115,200
Explanation:
If his money is compounded quarterly by 20%, therefore the added interest will be 20%of 8,000 which is 1,600/quarter of a year. This will be equivalent to (4×1600) compounded interest for 1year i.e 6,400
If he borrowed 8000 initially, the accrued amount after one year will be initial money borrowed + compound interest = 8000 + 6400
= 14,400
After 8years, she will would have own 8×14,400 which is equivalent to 115,200.
This shows that she must have own 115,200 after 8years