After the first year she will accumulate 1750×1.04255.

Then she will make another deposit of 1750, making the total amount 1750×1.04255+1750.

By the end of the second year she will have accumulated (1750×1.04255+1750)×1.04255.

Expanding this we get: 1750×1.04255²+1750×1.04255.

After fifteen years we have 1750×1.04255¹⁵+1750×1.04255¹⁴+...+1750×1.04255²+1750×1.04255.

This can be written 1750×1.04255(1.04255¹⁵-1)/(1.04255-1) (sum of a geometric progression).

This evaluates to 37,232.29. But, to find the interest we have to subtract the total amount invested which is 15×1750=26,250. So the interest is 10,982.29.