if the average ( arithmetic mean ) of a and b is 160 , and c – a = 200 , what is the average of b and c ?
"a + b / 2 = 160 = > a + b = 320 a = c - 200 . . . sub this value c - 200 + b = 320 = > c + b = 520 = > c + b / 2 = 260 answer : a"
subtract(multiply(200, const_2), multiply(160, const_2))