Three years ago, the average age of A and B was 18 years. With C joining them, the average age becomes 22 years. How old is C now?  Choose the correct choice from the following options.
A) 18 years
B) 24 years
C) 27 years
D) 28 years
E) None
Solution   Present age of (A+B)	= (18x2+3x2) years   = 42 years.   Present age of (A+B+C)	= (22x3) years   = 66 years.   ∴ C's age	= (66 - 42)= 
<gadget id="calculator">(66 - 42)</gadget>
<output>24</output>
24 years.   Answer 24 years
<result>B</result>
Three years ago, the average age of A and B was 18 years. With C joining them, the average age becomes 22 years. How old is C now?