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.
(1) Don't know anything about number of girls, cannot determine.
(2) We know that 26+a = Total
18+2a = Total
Therefore, 26+a=18+2a, find a, then find total