1.  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% ?

A. 370
B. 340
C. 320
D. 360

Answer: Option C

Explanation:

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.