[問題] Form32 Sec3-Q16

[sam6521]

Beth received 3/10 of the votes cast in a certain election. What fraction of the other votes cast would she have needed in order to have received 1/2 of the votes cast?

(A)1/5
(B)2/7
(C)3/10
(D)7/20
(E)1/2

Ans:(B)

[navywhite0425]

我是醬想的

假設10人
beth有3票了(要包括他自己一票)

題目問說
如果他要拿到一半
還需要多少票的fraction
所以就說還有7個人
他必須拿兩票
才會1/2
所以就是2/7嚕~

醬講可以嘛^^

[cohika]

這題可以這樣計算

設總votes數 X , 還需得到的比例為a
3/7*X + a (X-3/7*X) = 1/2*X
a=2/7