Concept:Use a single variable for the original pass and fail counts, then apply the second condition to form a ratio equation.Explanation:Let the number of passed candidates be 5x and failed candidates be x.So, total candidates appeared =5x+x=6x.In the second scenario:New total candidates =6x+21.New passed candidates =5x−11.New failed candidates =Total−Passed=(6x+21)−(5x−11)=x+32.Given the new ratio of passed to failed is 7:2:x+325x−11​=27​Cross-multiply:2(5x−11)=7(x+32)10x−22=7x+2243x=246x=82Original total number of candidates who appeared:6x=6×82=492Answer:492, i.e. Option D.