A batsman makes a score of 200 runs in the 17th inning and thus increases his averages by 10 What is his average after 17th inning?  Choose the correct choice:
A) 39 B) 35 C) 42 D) 40 E) 41.5

Rationale: "let the average after 16 th inning = x then total run after 16 th inning = 16 x then total run after 17 th inning = 16 x + 200 then average run after 17 th inning = ( 16 x + 200 ) / 17 ( 16 x + 200 ) / 17 = x + 10 = > 16 x + 200 = 17 x + 170 x = 30 ; average after 17 th inning = 30 + 10 = 40 answer : d"
Answer: D