Question 778182: Brandon gave directions to his house but decided not to give the house number. Instead , he gave his friends some clues to see who could find his house.
The number is greater than 50.
The number is less than 90.
The two digits are different.
The tens digit is larger than the ones digit.
It is an odd number.
The sum of its digit is 15 .
What is Brandon's house number?
Answer by KMST(5328)   (Show Source):
You can put this solution on YOUR website! "It is an odd number."
That tells you that the ones digit is odd. The number must end in 1, 3, 5, 7, or 9.
"The number is less than 90." AND "The sum of its digit is 15."
That tells you that it is a two-digit number, and the ones digit is either 7 or 9, because for a tens digit plus an odd ones digit to add to 15, the ones digit could not be 1, 3, or 5.
"The tens digit is larger than the ones digit."
That tells you that the ones digit cannot be 9 (because the tens digits must be larger), so the ones digit is 7. Then the tens digit could be 8, or 9.
With the tens digit being 9, the number would be 97, but that is not less than 90.
The only choice left is for the tens digit to be 8, and Brandon's house number is  .
NOTE:
I did not use:
"The number is greater than 50."
OR
"The two digits are different."
I did not need those facts.
They make the problem easier, because you are told some facts explicitly, but with just the other facts, you can figure out that it is a two digit number, and the two digits are different.
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