A, B and C enter into a partnership in the ratio 7/2 :4/3 :6/5 . After 4 months, A increases his share 50%. If the total profit at the end of one year be Rs. 21,600, then B's share in the profit is:

4000

Ratio of initial investments = \(\frac{7}{2}\) :\(\frac{4}{3}\):\(\frac{6}{5}\)

= 105:40:36

Let the initial investments be 105x, 40x and 36x.

A : B : C = [(105x × 4) + (210x × 8)] : [40x × 12} : [36x × 12]

= 1680x : 480x : 432x = 35 : 10 : 9

Hence, B's share = Rs. 21600 × \(\frac{10}{54}\)

= 4,000