Each of the 11 letters A, H, I, M, O, T, U, V, W, X and Z appears same when looked at in a mirror. They are called symmetric letters. Other letters in the alphabet are asymmetric letters. How many two letter computer passwords can be formed (no repetition allowed) with at least one symmetric letter? Choose the correct choice.
A) 2,420  B) 6,435  C) 12,100  D) 12,870  E) 25,740
Since we are given atleast one symmetric letter in the three letter word we can take the following cases   1. All two   2. One symmetry and other two non   4. All the two letters can be arranged in 2 ways   ( 11c2+ 11c1 * 15c2) *2   ( 11*10/ 2 + 11 * 15 * 14 / 2 ) * 2   2420   IMO option A is the correct answer..   O2,420 please...will correct if I missed anything..
<result>A</result>
Each of the 11 letters A, H, I, M, O, T, U, V, W, X and Z appears same when looked at in a mirror. They are called symmetric letters. Other letters in the alphabet are asymmetric letters. How many two letter computer passwords can be formed (no repetition allowed) with at least one symmetric letter?