if the average ( arithmetic mean ) of a and b is 110 , and the average of b and c is 150 , what is the value of a − c ?
"question : a - c = ? ( a + b ) / 2 = 110 = = = > a + b = 220 ( b + c ) / 2 = 150 = = = > b + c = 300 ( a + b ) - ( b + c ) = 220 - 300 = = = > a + b - b - c = - 80 = = = > a - c = - 80 answer : d"
subtract(multiply(150, const_2), multiply(110, const_2))