There is a two digit number with the unique property that if a decimal point is inserted between the two digits, the resulting number is the average of the digits. What is the number?

Let x = first digit, y = second digit.

x + y/10 = (x+y)/2

OR

x = (4/5)y

y must be a multiple of 5 for x to be an integer.

Therefore, the number is 45.

Posted by hoodat on 2007-05-04 09:18:37