In a row of 36 pupils, the first boy is followed by 1 girl, the second boy is followed by 2 girls, the third by 3 girls and so on. What is the number of girls in the second half of the row, if the row starts with the boy?
A15
B12
C16
D28
In a row of 36 pupils, the first boy is followed by 1 girl, the second boy is followed by 2 girls, the third by 3 girls and so on. What is the number of girls in the second half of the row, if the row starts with the boy?
A15
B12
C16
D28