Question

a batsman scored at an average some runs in 10 innings he scored 48 runs in the eleventh evening there by his average runs came down by two what were is average runs in 11th innings

Answer 1

Let the average for first 11 innings is y
From question 
11y + 90 = (y - 5) x 12
⇒ y = 150
∴ Average after 12th inning = (150 - 5)= 145

Answer 2

I hope it will help you dear...