In a examination out of 480 students, 85% of the girls and 70% of the boys passed. How many boys appeared in the examination, if total pass percentage was 75%?

Total number of students = 480
percentage of total students passed = 75% of total student
= (75 x 480)/100 = 360 students
Now, using the condition from the question.
Let the number of boys be N
Then, 70% of N + 85% of (480 - N) = 360
⇒ [(70 x N)/100] + [85 x (480 - N)]/100 = 360
⇒ 70N - 85N + 40800 = 36000
⇒ 40800 - 36000 = 85N - 70N
⇒ 4800 = 15N
⇒ N = 4800/15 = 320
∴ There are 320 boys who appeared for the examination,