Answer:
36
Explanation:
By the Fundamental Counting Principle, if there are x ways to choose one thing, y ways to choose another thing, and z ways to choose another thing, then there are x*y*z possible combinations of all of those things.
Here, there are 3 ways to choose a shift, 4 ways to choose a pair of pants, and 3 ways to choose a tie. Therefore, there are 3*4*3 = 36 different outfits that Gerald can make that include one shirt, pair of pants, and tie.