A five-digit number 2A78B, is divisible by 55. What is

Solution

2A78B 2A78B is divisible by 55 Or 11×5. So, divisibility rule of 11 and 5 given number can only be completely divided by 11 if the difference of the sum of digits at odd position and sum of digits at even position in a number is 0 or 11. If the last number is either 0 or 5, the entire number is divisible by 5.  Maximum possible value of A and B=6 and 5 Maximum possible value of A-B=6-5=1 Minimum value of A and B=1 and 0 Minimum value of (A-B) =1-0=1 Difference between the maximum and minimum possible value of (A-B) =1-1=0.