Question

一道英语数学题，求意思和过程

There is a line of five lattices. Please use three colour-red,green and black to dye them.Each lattice uses one colour.there are _____ways to dye them without two adjoint lattices both being green .
求答案

Answer 1

5个格子连成一条线，用红绿蓝三种颜色给每个格子涂色，问有几种情况可以不让两个绿色的挨着。
先选有两个绿色挨着的情况：4+1+3+2+1=11种。
所有的情况3*3*3*3=81种，
结论是81-11=70种。