SAT Subject Test Mathematics Level 1

The answer is (A).

PERMUTATIONS AND COMBINATIONS

To be successful with combinations and permutations questions like Example
8, you have to remember the relevant formulas.

PERMUTATIONS AND COMBINATIONS FORMULAS

The number  of  permutations    of  n   distinct    objects is  n!  =   n(n −   1)(n    −

2)···(3)(2)(1)

The number  of  permutations    of  n   objects,    a   of  which   are

indistinguishable,  b   of  which   are indistinguishable,  etc.,   is

The number  of  permutations    of  n   objects taken   r   at  a   time    is

The number  of  combinations    of  n   objects taken   r   at  a   time    is