Answer:
13 years after the declaration of independence, George Washington was inaugurated as the first president of the US. The answer is a two digit prime number
Solution:
We are asked to find out how many years after the declaration of independence was George Washington inaugurated as the first president of the US.
But we have been given some clue to find the number. The clues given to us are, the answer is a two digit prime number.
This clue narrows down the number of prime numbers we have to consider to get the correct answer.
The next clue given to us is, the ones digit of the answer is two more than tens digit.
Now let us forget about the first clue and try only based on the second clue to list out number that satisfy the given clue.
The numbers are:
13,24,35,46,57,68,79.
So, out of the numbers listed above only 13 and 79 are prime numbers, which satisfy both the clues given to us.
Now the third clue is, the product of the digit is a prime number.
So, 1 × 3=3
Which is a prime number.
And, 7 × 9=63.
Which is not a prime number.
Therefore the required answer is 13 years.