I would like to know why we don't prorate 9 / 12?

On April 1, Pujols, Inc., exchanges $524,500 for 70 percent of the outstanding stock of Ramirez Corporation. The remaining 30 percent of the outstanding shares continued to trade at a collective fair value of $204,400. Ramirezs identifiable assets and liabilities each had book values that equaled their fair values on April 1 for a net total of $625,000. During the remainder of the year, Ramirez generates revenues of $697,000 and expenses of $369,000 and declared no dividends. On a December 31 consolidated balance sheet, what amount should be reported as noncontrolling interest?

Ans. 302,800