If the sum of the first n positive integers is S, what is the sum of the first n positive integers divisible by 3, in terms of S ?
Pick:
A) S/2	B) S	C) 2S	D) 3S	E) 4S
Answer is 3S   Given sum of 1 2 3.....n = S   sum of 3 , 6 , 9 ....3n = 3[sum(1 2 3....n) ] = 3S
<result>D</result>
If the sum of the first n positive integers is S, what is the sum of the first n positive integers divisible by 3, in terms of S ?