A batsman makes a score of 90 runs in the 11th inning and thus increases his average by 5. Find his average after 11th inning.  Choose the correct choice from the following choices.
A) 40 B) 50 C) 62 D) 45 E) 56

Rationale: "let the average after 11 th inning = x then , average after 10 th inning = x - 5 10 ( x - 5 ) + 90 = 11 x x = 90 - 50 = 40 answer is a"
Answer: A