Question: the average age of an adult class is 40 years . 12 new students with an avg age of 34 years join the class . therefore decreasing the average by 4 years . find what was the original average age of the class ?
A) 6
B) 12
C) 16
D) 20
E) 22
Correct answer: A
Grade: 7 | Topic: Ratios and proportions | Difficulty: Medium | Standard: 7.RP.A.3