Out of 84 students, girls are thrice the boys. A boy is ranked 18th from top, and 13 girls are ahead of him. Find boys after him.
Show answer & explanation
Correct answer: D
Explanation
Step 1: Find the number of boys and girls.
Let the number of boys be B and girls be G.
Total students = 84
Given, G = 3B
⇒ B + 3B = 84
⇒ 4B = 84 ⇒ B = 21 (Total boys) and G = 63 (Total girls)
Step 2: Find the number of boys after the given boy.
The boy is ranked 18th from the top, which means there are 17 students ahead of him.
Number of girls ahead of him = 13
Number of boys ahead of him = 17 − 13 = 4 boys
Including the boy himself, total boys up to his rank = 4 + 1 = 5 boys
Number of boys ranked after him = Total boys − 5 = 21 − 5 = 16
Therefore, the correct option is (D).