Amit, Binod, and Chandu jointly started a business with initial investments of Rs. 'x', Rs. 'x + 2000', and Rs. '4x', respectively. After eight months, Amit and Chandu withdrew their respective investments, leaving Binod's investment active for the entire year. At the end of the year, the total profit earned by the business was Rs. (39x + 18,000). Determine the share of Binod in this profit.