3.设不及格人数为x77(150-x)+47x=55*1504.设甲余x元,乙余y元x/y=3/2(x+50)/(y+30)=7/65.设大宿舍x间,小宿舍y间x+y=308x+5y=198

Question

3.设不及格人数为x
77(150-x)+47x=55*150
4.设甲余x元,乙余y元
x/y=3/2
(x+50)/(y+30)=7/6
5.设大宿舍x间,小宿舍y间
x+y=30
8x+5y=198

Answer 1

77*150-77x+47x=55*150
30x=22*150
x=110
x=3y/2
6x+300=7y+210
9y+300=7y+210
2y=-90
y=-45
x=-67.5
x=30-y
240-8y+5y=198
3y=58
y=14
x=16