A boy was asked to calculate the arithmetic mean of ten positive integers each of which had 2 digits.
By mistake, he interchanged the two digits, a & b, in one of these ten integers. As a result, his answer for the arithmetic mean was 1.8 more than what it should have been.
Find the value of b-a.

Y + 10b-a =10(M+1.8)
Y+ 10a-b = 10M
9b-9a = 18
b-a =2

Posted by Mike on 2003-11-20 07:23:52