matt gets a $ 1,600 commission on a big sale . this commission alone raises his average commission by $ 150 . if matt ' s new average commission is $ 400 , how many sales has matt made ?
"let , average commission = x no . of items sold = y total commission = xy new commission = xy + 1600 new average = ( xy + 1600 ) / ( y + 1 ) = 150 + x i . e . ( xy + 1600 ) = ( y + 1 ) * ( 150 + x ) i . e . ( xy + 1600 ) = ( xy + x + 150 y + 150 ) i . e . ( 1450 ) = ( x + 150 y ) new commission = 400 = 150 + x i . e . x = 250 i . e . y = 8 new sales = y + 1 = 9 answer : option a"
divide(subtract(1,600, const_100), subtract(400, subtract(400, 150)))