Bill spent 50% of his savings on school supplies, and then he spent 50% of what was left on lunch. If he had $6 left after lunch, how much did he have in savings at the starting?

Work backwards to ?nd out the answer. After lunch Bill had $6. He had spent 50% (or 1/2 ) of what he had on lunch and 50% is what is left. Since $6 is 50% of what he had before lunch, he had $12 before lunch. Using the same reasoning, $12 is 50% of what he had before buying school supplies. Therefore, he had $24 when he began shopping.