这个题目为什么不选B呀,用条件B单独就可以推出总人数呀.请教各位XDJM呀!
18+2X=26+X 则X=8 总数为34人,不需要和条件并列的!
题目中的表格我画不出来,请大家看原题吧.
Q30:
Number Studying Number Not Total
Biology Studying Biology
Number 18
of Boys
Number
of Girls
Total 26
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. | 
