In a 90-student class, girls are double boys. If Rahul is 20th from top and 15 girls are ahead of him, find number of boys behind him.
Show answer & explanation
Correct answer: D
Explanation
Total students = 90
Girls = 2 × Boys(B)
So, B + 2B = 90
3B = 90 → B = 30
Boys = 30, Girls = 60
Rahul is 20th from top → 19 students above him
Girls above him = 15
So boys above him = 19 − 15 = 4
Total boys = 30
So boys behind = 30 – 4 - 1 = 25
Hence, the correct answer is option 4.