Answer:
378
Step-by-step explanation:
Work 1:
She has 9 kinds of cards out of which she has to chose only 1.
The number of ways of doing this is 9 (she can pick any one of them).
Work 2:
She has 7 kinds of cards out of which she has to chose only 1.
The number of ways of doing this is 7 (she can pick any one of them).
Work 3:
She has 3 designs of first-class stamps out of which she has to chose only 1.
The number of ways of doing this is 3 (she can pick any one of them).
Work 4:
She has to pick the color of pen and she has 2 to choose from.
The number of ways of doing this is 2 (she can choose any one of them).
She has to do Work 1 and Work 2 and Work 3 and Work 4.
∴By the fundamental counting principle, the total number of different ways in which the thank-you note can look is 9×7×3×2 = 378
