HOW DO COLLEGE STUDENTS PAY FOR TAXES?

I already know that scholarships and grants used to pay for tuition, fees, and books are not taxable, but scholarships used to pay for room, board, and food are. Let's say that room and board cost $20,000, and I receive exactly $20,000 in aid to cover that cost. How in the world would I be able to pay taxes if that entire $20,000 was paid to cover room and board?