Karan and Arjun started a business by investing their capitals in the ratio 3:4, respectively. After 8 months Karan increased his investment by Rs. 3,000 while Arjun decreased his investment by Rs. 2,000. Find the total initial investment done by Karan and Arjun together if the profit earned by Karan is Rs. 19,500 out of the total profit earned by both of them at the end of 1 year, which is Rs. 42,500?

Let the initial investment done by Karan be 'Rs. 3x' So, initial investment done by Arjun = 3x X (4/3) = Rs. '4x' Profits sharing ratio between Karan and Arjun = [{3x X 8 + (3x + 3000) X 4}:{4x X 8 + (4x - 2000) X 4}] = (36x + 12000):(48x - 8000) According to the data given: 19500:42500 = (36x + 12000):(84x + 4000) Or, 39:85 = (36x + 12000):(84x + 4000) Or, 3276x + 156000 = 3060x + 1020000 Or, 3276x - 3060x = 1020000 - 156000 Or, 216x = 864000 So, x = 4000 So, total initial investment done by Karan and Arjun together = {(3 + 4) X 4000} = Rs. 28,000 Hence, the correct answer is B.