a batsman makes a score of 90 runs in the 11 th inning and thus increases his average by 5 . find his average after 11 th inning .
"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"
add(subtract(90, multiply(11, 5)), 5)