Answer :
12 possible outcomes.
Sweater A
Sweater B
Sweater C
Skirt 1
Skirt 2
Skirt 3
Skirt 4
Possible ways:
A1, A2, A3, A4
B1, B2, B3, B4
C1, C2, C3, C4
Sweater A
Sweater B
Sweater C
Skirt 1
Skirt 2
Skirt 3
Skirt 4
Possible ways:
A1, A2, A3, A4
B1, B2, B3, B4
C1, C2, C3, C4
She can choose any one of 3 sweaters. For each choice of sweater . . .
She can choose any one of 4 skirts.
The total number of different ways to choose an outfit = (3 x 4) = 12 .