Q. The average marks obtained by 22 candidates in an examination are 45. The average marks of the first ten are 55 and that of the last eleven are 40. The number of marks obtained by the 11th candidates is-

Explanation by: Indresh Gehalot

Here's how to solve the problem:
 * Calculate the total marks of all 22 candidates:
   * Total marks = 22 candidates * 45 marks/candidate = 990 marks
 * Calculate the total marks of the first 10 candidates:
   * Total marks = 10 candidates * 55 marks/candidate = 550 marks
 * Calculate the total marks of the last 11 candidates:
   * Total marks = 11 candidates * 40 marks/candidate = 440 marks
 * Calculate the combined total marks of the first 10 and last 11 candidates:
   * Combined total marks = 550 marks + 440 marks = 990 marks
 * Determine the 11th candidate's marks:
   * Since the combined total marks of the first 10 and last 11 is equal to the total marks of all 22 candidates, this means the 11th candidate's mark is included in both the first 10 and last 11.
   * Marks of 11th candidate = Total marks(first 10) + Total marks(last 11) - Total marks(all 22) = 990-990 = 0.
Therefore, the 11th candidate obtained 0 marks.
The answer is (A).