The youngest of 4 children has siblings who are 3, 6, and 7 years older than she is. If the average (arithmetic mean) age of the 4 siblings is 30, what is the age of the youngest sibling?	Choose the correct choice
A) 22 B) 23 C) 24 D) 25 E) 26

Rationale: "x + ( x + 3 ) + ( x + 6 ) + ( x + 7 ) = 120 4 x + 16 = 120 4 x = 104 x = 26 the answer is e ."
Answer: E