Finding number of different passwords

How many different computer passwords are possible?

a.If each password consists of 3 symbols and if the first one must be a number and the other 2 must be letters

b.If each password consists of 3 symbols and if the first one must be a Letter and the other 2 must be Numbers

c.Which one do you believe is more secure and why?

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...ust be letters
I assume that password is not case sensitive and repetition is allowed
Possible number passwords=10*26*26= 6760
If repetition is not allowed
Possible number passwords=10*26*25= 6500 ...