A solution was prepared by mixing 10.00 mL of unknown (X) with 5.00 mL of standard (S)

Question:

A solution was prepared by mixing 10.00 mL of unknown (X) with 5.00 mL of standard (S) containing 8.24 g S/mL and diluting the mixture to 50.0 mL. The measured signal quotient was (signal due to X/signal due to S) 1.690/1.000.
(a) In a separate experiment, in which the concentrations of X and S were equal, the quotient was (signal due to X/signal due to S) 0.930/1.000. What is the concentration of X in the unknown?
(b) Answer the same question if, in a separate experiment in which the concentration of X was 3.42 times the concentration of S, the quotient was (signal due to X/signal due to S) 0.930/1.000.