Equilibrium problem?

Question

This equilibrium problem has been killing me for quite a while. Any help appreciated greatly! Thanks

In an experiment, 3.00 mL of 0.0698 M A, 2.00 mL of 0.0845 M B, and 5.00 mL of distilled water are mixed in a beaker. After the reaction has reached equilibrium, the absorbance of the product C is measured and its concentration is determined to be 0.00605 M. Calculate the equilibrium constant for this reaction.

A(g) + B(g) <->C(g)

Answer 1

K = [C]/[A][B]

The total volume is 3+2+5=10ml

The concentration of A is 0.0698*3/10 =0.02094
The concentration of B is 0.0845*2/10= 0.0169

so K = 0.00605/(0.02094)(0.0169)=17

I am not sure , but if some ideas can help