Grandpa's age this year is 6 times that of Xiaoming's. A few years later, grandpa's age is 5 times that of Xiao Ming's, and a few years later, grandpa's age is 4 times that of Xiao Ming's. How old is grandpa this year?
今年爷爷的年龄是小明的6倍．几年后爷爷的年龄是小明的5倍，又几年后，爷爷的年龄是小明的4倍．爷爷今年是多少岁．
<result>72</result>