This Problem Set is a part of the Lesson 4, Unit 8, Grade 7. A carnival game has 160 rubber ducks floating in a pool. The person playing the game takes out one duck and looks at it. If there's a red mark on the bottom of the duck, the person wins a small prize. If there's a blue mark on the bottom of the duck, the person wins a large prize. Many ducks do not have a mark. After 50 people have played the game, only 3 of them have won a small prize, and none of them have won a large prize. Estimate the number of the 160 ducks that you think have red marks on the bottom.