question_answer 7)

The numbers 13 and 31 are prime numbers. Both these numbers have same digits 1 and 3. Find such pairs of prime numbers upto 100.

Answer:

                All prime numbers upto 100 are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89 and 97. Out of these prime numbers, a pair of prime numbers having same digits are (i) 13, 31                               (ii) 17, 71                              (iii) 37, 73                             (iv) 79, 97 Hence, there are 4 pairs of such types.