RS. N/6 for M/ 6 months. B invests Rs. N/3 for M/3 months and C invests Rs. [N - (N/6 + N/3)]For M months.Ratio of their INVESTMENT = (N/6 x M/6) : (N/3 x M/3) : (N / 2NM)= 1/36 : 1/9 : 1/2 = 1 : 4 : 18 B's SHARE = Rs. 4600 x (4/23) = Rs. 800