Lindsay and Kiana work at the same restaurant. Lindsay earns $12.75 per hour and Kiana, who has been working there longer, earns $15.25 per hour. One week, both girls work the same number of hours at the restaurant, but Lindsay spends $37 and Kiana spends $55. At the end of the week, Lindsay has more money left than Kiana. What is the smallest number of hours the girls could have worked for this to be true?