There are five numbers A, B, C, D, and E. It is known that A is half of B, B is half of C, C is half of D, and D is half of E. The average of these five numbers is 3.1. How much is E?
有A、B、C、D、E五个数，已知A是B的一半，B是C的一半，C是D的一半，D是E的一半，这五个数的平均数是3.1，求E是多少？
<result>8</result>