In an examination, 49% students failed in English, 36% students failed in Hindi, While 15% failed in both. if total number of passed students in 450, then how many students did appear in the examination?

According to the formula .
Percentage of students passed in both the subjects
= [100 - (x + y - z)]%
= [100 - (49 + 36 - 15)]% = 30%
Let total number of students = N
According to the question,
(N x 30)/100 = 450
⇒ N = (450/30) x 100 = 1500
∴ Total number of students = 1500