Task: Question Answering
Input (English): The average (arithmetic mean) of \(2a\) and \(b\) is 15 and the average of \(2a\),\(b\), and \(3c\) is 20. What is the value of \(c\)?
(A)5 (B)10 (C)15 (D)20 (E)25
Output (English): B