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 45, what is the value of a?	Choose the correct choice from the following.
A) 21 B) 25 C) 28 D) 30 E) 33
Let a=2k, b=3k, and c=4k.   a+b+c = 2k+3k+4k = 9k   Since the average is 45:   9k/3 2 +3 +4= 
<gadget id="calculator">2 +3 +4</gadget>
<output>9</output>
9k   Since the average is 45:   9k/3= 45   3k = 45   k=15   Then a=30.   The answer is 30.
<result>D</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 45, what is the value of a?