Mr. Smith calculated the average of 10three digit numbers. But due to a mistake he reversed the digits of a number and thus his average increased by 49.5. The difference between the unit digit and hundreds digit of that number is :  Choose the most appropriate option
A) a) 4
B) b) 3
C) c) 2
D) d) 1
E) e) 5
Since the average increased by 49.5 and there were a total of 10 numbers, it means the incorrect number was 495 greater than the correct number.   Say, the correct number was abc (where a, b and c are the digits of the 3 digit number)   Then the incorrect number was cba.   100c + 10b + a - (100a + 10b + c) = 495   99c - 99a = 99(c - a) = 495   495 = 99*5 = 99(c - a)   So c - a = 5   Answer (e) 5)
<result>E</result>
Mr. Smith calculated the average of 10three digit numbers. But due to a mistake he reversed the digits of a number and thus his average increased by 49.5. The difference between the unit digit and hundreds digit of that number is :