The average of class in 35 yr. 6 new students with an average age of 33 yr. joined in that class, there by decreasing the average by half year. The original strength of the class was
Correct Answer: 18
Explanation:
Let the number of students in the class = N
According to the question,
(35N + 6 x 33) / (N + 6) = 35 - (1/2)
⇒ 35N + 198 = 34.5 (N + 6)
⇒ 35N +198 = 34.5N + 207
⇒ 0.5N = 207 -198N = 9/0.5 = 18
∴ N = 18 days
