The youngest of 4 children has siblings who are 3, 5, and 8 years older than she is. If the average (arithmetic mean) age of the 4 siblings is 20, what is the age of the youngest sibling?  Choose the correct answer:
A) 14	B) 15	C) 16	D) 17	E) 18
x + (x+3) + (x+5) + (x+8) = 80   4x + 16 = 80   4x = 64   x = 16   The answer is 16.
<result>C</result>
The youngest of 4 children has siblings who are 3, 5, and 8 years older than she is. If the average (arithmetic mean) age of the 4 siblings is 20, what is the age of the youngest sibling?