$A$ and $B$ started a business together and the respective ratio between the investments of $A$ and $B$ was $5:9$. After $4$ months from the start of business, $C$ joined the business and the respective ratio between investments of $B$ and $C$ was $3:7$. If the annual profit earned by them was $\$ 7084$, what is $C$'s share in the profit?
My solution:
Ratio of investments of $A,B,C = 5:9:21$
Ratio of profits $= (5*12):(9*12):(21*8)=5:9:14$
Therefore $C$'s share$= (14/28)*7084=3542$
Is this the correct answer? In textbook, the correct answer is given as $\$ 3527$. Which one is correct?