The ratio of a to b to c is 2 to 3 to 4, and a, b, c are positive integers. If the average (arithmetic mean) of the three numbers is 36, what is the value of a?  Choose the most appropriate option.
A) 21  B) 24  C) 25  D) 27  E) 30
Let a=2k, b=3k, and c=4k.   a+b+c = 2k+3k+4k = 9k   Since the average is 36:   9k/3 2 +3 +4= 
<gadget id="calculator">2 +3 +4</gadget>
<output>9</output>
9k   Since the average is 36:   9k/3= 36   3k = 36   k=12   Then a=24.   The answer is 24.
<result>B</result>
The ratio of a to b to c is 2 to 3 to 4, and a, b, c are positive integers. If the average (arithmetic mean) of the three numbers is 36, what is the value of a?