the average of 1 st 3 of 4 numbers is 16 and of the last 3 are 15 . if the sum of the first and the last number is 19 . what is the last numbers ?
"a + b + c = 48 b + c + d = 45 a + d = 19 a – d = 3 a + d = 19 2 d = 16 d = 8 answer d"
subtract(subtract(multiply(3, 16), add(subtract(19, 16), 3)), 16)