ceach of the eleven letters A,H,I,M,O,T,U,V,W,X,Z appears same when looked at in a mirror . they are called symmetric letters .other letters in the alphabet are asymmetric letters . ho many three letter computer passwords can be formed (no repetition allowed) with atleast one symmetric letter 

Dear Student,
Please find below the solution to the asked query:

We haveA,H,I,M,O,T,U,V,W,X,Z  i.e. 11 symmetric lettersAsymmetric letters=26-11=15Number of selection with atleast one symmetric letter=1 Symmetric and 2 Asymmetric  OR 2 Symmetric and 1 Asymmetric  OR 1 Symmetric=11C1×15C2+11C2×15C1+11C3=11×15×142×1+11×102×15+11×10×93×2×1=1155+825+165=2145For each of these selections, threre will be 3! arrangements.Hence:Total passwords=3!×2145=6×2145=12870 Answer

Hope this information will clear your doubts about this topic.

If you have any doubts just ask here on the ask and answer forum and our experts will try to help you out as soon as possible.
Regards

  • 1
What are you looking for?