Problem
10. Whenever Hannah turns on her cell phone, it randomly shows a background image from a group of 6 images Hannah has selected. Of the 6 images Hannah has selected, - exactly 2 are of her friends, - exactly 3 are of her family members, and - exactly 1 is of her pet dog. What is the probability that the cell phone shows an image other than the pet dog the next time Hannah turns on her cell phone?
Solution
Step 1 ：\(P(\text{not pet dog}) = \frac{\text{number of non-pet dog images}}{\text{total number of images}}\)
Step 2 ：\(P(\text{not pet dog}) = \frac{2 + 3}{6}\)
Step 3 ：\(P(\text{not pet dog}) = \frac{5}{6}\)
