The width should be 32 inches.
Interest gained for a particular period equals to Money invested (kept) in Savings account for that period <em>multiplied by </em>Interest accrued on this money.
Therefore, Accrued interest i(x) = h(x) * s(x) = 200 * [ (1.05)x - 1 ],
where x is the number of years for which money is invested.
So, new function i(x) = (210)x - 200 .