Kevin, Barbara, and their mother and father went backpacking in Yosemite National Park. On the first and second days, each hiker had a serving of food for
breakfast, lunch, and dinner. A large, noisy, brown bear barged into camp the
second night, got the food pack down from the tree where they had hung it, and
ate one half of the food that was left. The next morning, after they all had
breakfast, they found they had 4 food servings left. They decided they had better
hike back to their car. How many servings of food did they begin the trip with?