"The average age of an adult class is 40 years. 12 new students with an averag
Channel: Doubtnut
Date: 05/04/2020

"The average
 age of an adult class is 40 years. 12 new students with an average age of 32
 years join the class, thereby decreasing the average by 4 years. The original
 strength of the class was
(a) 10 (b) 11 (c) 12 (d) 15"