Let B1=no of biys with brown hair
B2=no of boys with other hair
G1=no of girls with brown hair
G2=no of girls with other hair
ask if (b1+g1)/(b1+b2+g1+g2)> 0.5
1 0.7(b1+b2)=b1
2 0.3(b1+b2+g1+g2)=g1
given 1
b1=35 b2=15
g1=0 g2=50
.35<.5
b1=35 b2=15
g1=50 g2=0
0.85>0.5
故1不足
given 2
let g1=30 g2=30
b1=30 b2=10
0.5
let g1=30 g2=0
b1=0 b2=70
0.3
故2不足
1.2
他說30%的全部孩子是女的有brown頭髮
且男生中70%有褐髮
問是否全部小孩中大於50%有褐髮
即是問是否男生有褐髮站全部的小孩大於20%
全部100個
g1=30
b1=25
b2=11
g2=34
55%
g1=30
b1=10
b2=4
g2=56
40%
故12核起來不足
※ 引述《pilichat (人生需要不斷冒險)》之銘言：
: 86. 7962-!-item-!-187;#058&005867
: Do more than 50 percent of the children in a certain group have brown hair?
: (1) 70 percent of the boys in the group have brown hair.
: (2) 30 percent of the children in the group are girls with brown hair.
: 請教一下這題可以列式解嗎？
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