the average of 10 numbers is 40.2 . later it is found that two numbers have been wrongly copied . the first is 19 greater than the actual number and the second number added is 13 instead of 31 . find the correct average .
"sum of 10 numbers = 402 corrected sum of 10 numbers = 402 – 13 + 31 – 19 = 401 hence , new average = 401 ⁄ 10 = 40.1 answer e"
divide(subtract(add(multiply(40.2, 10), add(13, 19)), 31), 10)