Answer:
The number of different smoothies Darrell can make is calculated by multiplying the number of options for each ingredient. To make the smoothie, Darrell first has to choose one of the 4 kinds of fruit. Then he has to choose one of the 2 kinds of juice. Finally, he has to choose one of the 9 flavors of frozen yogurt.
So, the number of different smoothies Darrell can make is 4 x 2 x 9 = 72.
Therefore, Darrell can make 72 different smoothies.