# What is the number ?

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A two digit number obtained by either multiplying the sum of the digit by 8 and adding 1 or by multiplying the difference of digits by 13 and adding 2 .

What is the number ?

posted Sep 3, 2014

## 1 Solution

The digit must be 41.

solution Nov 7, 2014

Similar Puzzles

Starting with any number at all, I can always reduce it to 4 by applying a consistent rule. 4 is the magic number.
Example: 100. 100 is 10, 10 is 3, 3 is 5, 5 is 4, and 4 is the magic number.
Another Example: 52. 52 is 8, 8 is 5, 5 is 4, 4 is the magic number.
Find out what is the rule?

There are 20 people standing in a line, one behind the other. Each is made to wear a hat, which can either be white or black. There can be any number of white or black hats between 0 and 20. Each person can see the hat of all the persons ahead of him in the line, but not those of the people standing behind. Each person is required to guess (loudly) the color of his/her own hat. The objective is for the group to get as many correct guesses as possible. The group is allowed to discuss and form a strategy before the exercise.
What is the best strategy?
What is the maximum number of correct guesses in this strategy?