the average of 25 results is 8 . the average of first 12 of them is 14 and that of last 12 is 17 . find the 13 result ?
"13 th result = sum of 25 results - sum of 24 results 18 * 25 - 14 * 12 + 17 * 12 = 78 answer is d"
subtract(subtract(multiply(25, 8), multiply(12, 17)), multiply(12, 14))