GRE Section45-3 怎么算

问题描述:

GRE Section45-3 怎么算
the daily rate for hotel that sleeps 4 people is 39dollars for one person and x dollars for each additional person.if 3 people take the room for one day and each pays 21dollars for the room what is the value fo
a)4 b)8 c)12 d)13 e)14

1个人39元
2个或以上39+nx
21X3=39+3X
63=39+3X
21=13+X
X=8