The total cost, $C, of renting a booth at the flea market, consists of a fixed amount of Sp and a variable amount which is q% of the revenue, $x, at the booth. (i) Write down an equation connecting C, p. q and x. When the revenue is $600, the rental cost is $165. When the revenue is $1200, the rental cost is $285. (ii) Form a pair of simultaneous equations in p and q and solve the equations to find the revenue at the booth if the total rental cost is $560.