Answer 54

The answer to the riddle – #54 The Safe

Answer

As per given conditions, there are three possible combinations for 2nd, 3rd and 4th digits. They are:

3, 0, 7 or

4, 1, 8 or

5, 2, 9

It is given that there are 3 pairs whose sum is 11. All possible pairs are

2, 9

3, 8

4, 7

5, 6

Now required number is 5 digit number and it contains 3 pairs of 11. So it must not be having 0 and 1 in it.

Hence, the only possible combination for 2nd, 3rd and 4th digits is

5, 2, 9

Also, the 1st digit is thrice the last digit. The possible combinations are

3, 1

6, 2

9, 3

Out of these only (6, 2) with (5, 2, 9) gives 3 pairs of 11. Hence, the answer is 65292.