英语翻译

问题描述:

英语翻译
There were 8 persons at a brithday party.Everyone shook hands with one another.Nobody shook hands with the same person twice.How many handshakes were exchanged at the party?

生日聚会上共有8个人.每个人都和另一个人彼此握手.没人和同一个人握两次手.那么,在聚会上,这些人一共交换握了几次手?