Answer:
71 girls
Explanation:
The class has 100 students.
It consists of 13 girls with no boyfriends, and the rest are "triplets" (B+2G groups)
If we subtract the 13 girls, the triplets must add up to 87 students.
The number of triplets is 87/3 = 29.
29(B + 2G) = 29B + 58G
The triplets consist of 29 boys and 58 girls with boyfriends.
No. of girls = girls with boyfriends + girls with no boyfriend
= 58 + 13
= 71
There are 71 girls in the class.