Q: Ali had a collection of seashells. He started with 180 seashells. He then gave away 40 seashells to his friends. He also gave 30 seashells to his brothers. If he sold half of the remaining seashells, how many seashells did he have left?
A: 55
Explain how we arrive at this answer:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
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Explanation: When he gave 40 seashells to his friends, Ali had 180 - 40 = 140 seashells. When he gave another 30 seashells to his brothers, he had 140 - 30 = 110 seashells. He also sold half of the seashells, a total of 1 / 2 * 110 = 55 seashells. He was left with 110 - 55 = 55 seashells.