**Problem of the week**** **

How many numbers can be formed from some or all of the digits 2,3,4,5 if no number is to have repeated digits ?

Solution:

The number can be of 1,2,3 or 4 digits. Of these types there are respectively, 4, 4X3,4X3X2 and 4X3X2X1 numbers that can be formed from the digits 2,3,4,5 without repetition.

So, in all, there are

4+12+24+24

=64 numbers.

Correct solution received from:

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