The average of the two-digit numbers, which remain the same when the digits interchange their positions, is__________?
Q1. The average of the two-digit numbers, which remain the same when the digits interchange their positions, is__________?
Answer: 55
Explanation: Two-digit numbers unchanged on reversing digits are 11, 22, 33, …, 99 (nine numbers); their average = (11 + 99)/2 = 55.