a) Rs. 100
b) Rs. 150
c) Rs. 200
d) Rs. 300

Answer: b
Explanation:
$$\eqalign{ & {\text{Let total capital}} = {\text{Rs}}{\text{.}}\,{\text{x}} \cr & {\text{Then, A’s capital}} = {\text{Rs}}{\text{.}}\,\frac{x}{3} \cr} $$
B’s capital = (A + C)’s capital ⇒ 2(B’s capital)
B’s capital = (A + B + C)’s capital = Rs. x
$$\eqalign{ & {\text{B’s capital}} = {\text{Rs}}{\text{.}}\frac{x}{2} \cr & {\text{C’s capital}} = {\text{Rs}}{\text{.}}\left[ {x – \left( {\frac{x}{3} + \frac{x}{2}} \right)} \right] \cr & = {\text{Rs}}{\text{.}}\,\frac{x}{6} \cr & \therefore {\text{A}}:{\text{B}}:{\text{C}} = \frac{x}{3}:\frac{x}{2}:\frac{x}{6} \cr & = 2:3:1 \cr & {\text{C’s share}} = {\text{Rs}}{\text{.}}\left( {900 \times \frac{1}{6}} \right) \cr & = {\text{Rs}}{\text{.}}\,{\text{150}} \cr} $$