gwd-22-32

The table above shows the number of students in a certain high school class who are boys and the number of students in the class who are studying biology.  What is the total number of students in the class?

(1)     Of the boys in the class, 15 are studying biology.

(2)   The number of girls in the class is twice the number of students in the class who are not studying biology.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

Answer:

答案是b，可我怎么觉得是c啊，大家帮忙看看

up?????

我也算出Ｃ耶

請問答案Ｂ是怎麼算的

請指教，謝謝．

我看看，以前没有作出来！

1单独推不出！

2，女孩数量等于x，则没学b的人x/2

26+x/2=18+x x可解，则总人数可得！

同意B

条件(2)的意思是女仔人数是不学习生物学的人数的2倍，而不是“女仔人数是不学习生物学的女仔人数的2倍

算出來囉

設Number Not
            Studying Biology = X

Number of Girls就會 = 2X

26+X = 18 + 2X

算出 X = 8

26 + 8 = 34 (全班人數)