Question

Babies born in the United States must have a Social Security card issued before their third birthday. How many different cards could be issued using the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9, if each card needs a nine-digit number and the digits can only be used once per card?

http://test.edperformance.com/graphics/math/12355.gif

Answer 1

each of the 9 places can be filled by any of the 10 digits

ex: the first palce can be filled by any of the 10 digits, so 10 options for that

similarly, 10 options for the rest

so, 10*10*10*10*10*10*10*10*10 = 10^9

Answer 2

thnx

Answer 3

welcome!