GWD 8-30
The 18 students in a certain high school class are boys and 26 students in the class studing biology. What 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.
我覺得第二個條件就已經充分, if the number of girls in the class are 2X, then the number NOT studying biology is X, so 26+X=18+2X=total
但是解答是(C), 請熊熊們幫幫忙吧?