A batsman in his 11th inning scores 88 runs, thereby increasing his average score by 4. What is his average after the 11th innings?

48

Let average score before 11th inning be x

Total score till 10th inning = x × 10 = 10x

Total score after 11th inning = 10x + 88 .......(1)

Average increases by 4 after 11th inning then,

New average = x + 4

Total runs scored after 11th = (x + 4) x 11  .....(2)

Since eq(1) and eq(2) are equal

⇒ 10x + 88 = 11x + 44

⇒ x = 44

Average after 11th inning = x + 4 = 48