Alice collected stamps for 7 weeks. She counted the number of stamps in her collection every week. By week 2, there had been 7 stamps collected. How many stamps did Alice collect between week 5 and week 7? A. 5 B. 6 C. 17 D. 22
What we can do to solve this problem is the following rule of three: 2 weeks ---> 7 stamps 7 weeks ---> x Clearing x we have: x = (7/2) * 7 = 24.5 The other rule of three is: 2 weeks ---> 7 stamps 5 weeks ---> x Clearing x we have: x = (5/2) * (7) = 17.5 You have the following inequality 17.5 <x <24.5 Thus x = 22 answer: Alice collect between week 5 and week 7, 22 stamps. D.22
