Final answer:
The available amount for store supplies at the fiscal year end cannot be determined from the provided data, which includes financial figures in millions and unrelated sample scenarios.
Step-by-step explanation:
The available amount for store supplies at the fiscal year end cannot be accurately determined with the given data. However, based on some provided financial figures such as $15 million, $17.4 million resulting from discounting $20 million by a 15% rate for one year, and $18.9 million from discounting $25 million by the same rate over two years, it's clear that the available amounts involve millions, not hundreds or thousands. Yet this does not indicate the exact amount for store supplies at year end since those figures do not relate directly to the store supplies budget.
The information provided involving a sample of 200 students and the expectation of them receiving $250 or more, as well as various totals from different contexts, do not help in determining the fiscal year end amount for store supplies.