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There are 11 alphabets A, H, I, M, O, T, U, V, W, X, Y, Z. They are called symmetrical alphabets. The remaining alphabets are known as asymmetrical alphabets.

How many four-lettered passwords can be formed by using symmetrical letters only? (repetitions not allowed)

1. $1086$
2. $255$
3. $7920$
4. None of these

These are 12 letters

No repetition is allowed so possible number of passwords of four letters

 12 11 10 9

=12*11*10*9

=11880

If There are 11 letters

No repetition is allowed so possible number of passwords of four letters

 11 10 9 8

=11*10*9*8

=7920

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