趣味的數學-64

某人收到一張支票，支票票面上寫有一定數額的美元和美分。當他兌現支票時，銀行出納員把支票的美元和美分的數額弄顛倒了：美元的數額變為美分，美分的數額變為美元。此人花了$3.50後，意識到他所剩餘的金額是原始支票金額的兩倍。問原始支票的金額是多少？

【原文】

Somebody received a check, calling for a certain amount in dollars and cents. When he cashed the check, the teller made a mistake, paying him in dollars the amount written in cents, and vice-versa. Later after spending $3.50, he suddenly realized that he had twice the amount called for by the check. What was the amount on the check?

【引自 The American Mathematical Monthly [AMM]，1941，problem E430】