【题目】1997年,王先生、王太太、王小明和王小芬一家的平均年齡是14歲.数年後,王小強出生了,2017年的今天,他們一家的平均年齡是30歲,求王小強的出生年份In 1997, the average age of a family of four,namely Mr. Wong, Mrs. Wong, Mickey Wongand Fanny Wong, was 14 Several years later,Kenny Wong w...