Question

five friends, billy, joe, eduardo, mary, and xavier, want one photograph of each possible pair of friends. use B, J, E, M, and X, and list all of the pairs that need to be photographed.

Answer 1

5C2
use formula nCr = n!/((n-r)!r!)

Answer 2

ok, thank you

Answer 3

wait, it says list all of the pairs that need to be photographed..

Answer 4

sorry, i means here "each possible pair of friends" is like
BJ, BE, BM, BX, ....

Answer 5

ok got it