Question

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

Answer 1

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