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

Five
letters are written to five different persons and their addresses are on 5
envelopes. Find in now many ways letters can be placed in envelopes so that no
letter is placed in the correct envelope.

Solution:

For five envelopes A B C D and E taking b, we get

Similarly
if c is sent to A there will be 11 ways. Hence total - 4x11 = 44 ways.

Correct solution received from:

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