+42 What is the arithmetic mean of all of the positive two-digit integers with the property that the integer is equal to the sum of its first digit plus its second digit plus the product of its two digits?
+1768 The only two-digit numbers that satisfy this condition are 11, 22, 33, 44, 55, 66, 77, 88, and 99.
Calculating the arithmetic mean
To find the arithmetic mean, we add all the numbers and divide by the total count.
Mean = (11 + 22 + 33 + 44 + 55 + 66 + 77 + 88 + 99) / 9
Mean = 495 / 9
Mean = 55
Therefore, the arithmetic mean of all positive two-digit integers satisfying the given condition is 55.
