The average age of an adult class is 40years. 10 new students with an avg age of 32years join the class. Therefore
decreasing the average by 4year. Find what was the original strength of class?	Options.
A) 10
B) 12
C) 15
D) 17
E) 18

Rationale: "let original strength = y then , 40 y + 10 x 32 = ( y + 10 ) x 36 â ‡ ’ 40 y + 320 = 36 y + 360 â ‡ ’ 4 y = 40 â ˆ ´ y = 10 a"
Answer: A