Respuesta :
Answer:
[tex]70[/tex]
Step-by-step explanation:
GIVEN: two two-letter passwords can be formed from the letters A, B, C, D, E, F, G and H.
TO FIND: How many different two two-letter passwords can be formed if no repetition of letters is allowed.
SOLUTION:
Total number of different letters [tex]=8[/tex]
for two two-letter passwords [tex]4[/tex] different are required.
Number of ways of selecting [tex]4[/tex] different letters from [tex]8[/tex] letters[tex]=^8C_4[/tex]
[tex]=\frac{8!}{4!4!}[/tex]
[tex]=70[/tex]
Hence there are [tex]70[/tex] different two-letter passwords can be formed using [tex]8[/tex] letters.
