The number of rooms at Hotel G is 10 less than twice the number of rooms at Hotel H. If the total number of rooms at Hotel G and Hotel H is 425, what is the number of rooms at Hotel G ?
140
180
200
240
280
题目分析:
设 Hotel H 的房间数量是 ~$x$~, Hotel G 的房间数量是 ~$y$~.根据题目中的两个条件列一元二次方程组:~$y=2x-10$~ and ~$x+y=425$~.把 ~$y=2x-10$~ 代入 ~$x+y=425$~,可得 ~$x+2x-10=425$~,~$3x=435,x=145$~,则 ~$y=280$~.则 Hotel H 是 145 个房间,Hotel G 是 280 个房间。
综上:答案就是 E.
G是H的两倍还少10 ,所以H+2H-10=425 H=145 G=280