1970 AHSME Problem 22

If the sum of the first 3n positive integers is 150 more than the sum of the first n positive integers, then the sum of the first 4n positive integers is

\textbf{(A) }300\qquad \textbf{(B) }350\qquad \textbf{(C) }400\qquad \textbf{(D) }450\qquad \textbf{(E) }600

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.