15,000
Since her interest is simple, it adds the 10% to the original amount.
So, we multiply her amount (10,000) by the interest rate (.1) and by the amount of years (5).
10,000 * .1 * 5= 5,000
This is how much she has gained from said interest. Adding this to 10,000 gives us 15,000, which is the amount she will have.
Another way to do this would be to make a chart/table:
Start: 10,000
1. 11,000
2. 12,000
3. 13,000
4. 14,000
5. 15,000
And thus, we get the same answer.
