a batsman makes a score of 87 runs in the 17 th inning and thus increases his average by 4 . find his average after 17 th inning .
"let the average after 17 th inning = x . then , average after 16 th inning = ( x – 4 ) . ∴ 16 ( x – 4 ) + 87 = 17 x or x = ( 87 – 64 ) = 23 . answer c"
add(subtract(87, multiply(17, 4)), 4)