A batsman makes a score of 120 runs in the 10th inning and thus increases his average by 10 Find his......

A batsman makes a score of 120 runs in the 10th inning and thus increases his average by 10. Find his average after 10 innings?

Let the average after 10th inning = x 
Then, average after 9th inning = (x-10)
9(x-10)+120 = 10x
x = 30

By: bhavesh kumar singh