Problem:
Four girls - Mary, Alina, Tina, and Hanna - sang songs in a concert as trios, with one girl sitting out each time. Hanna sang 7 songs, which was more than any other girl, and Mary sang songs, which was fewer than any other girl. How many songs did these trios sing?
Answer Choices:
A.
B.
C.
D.
E.
Solution:
Tina and Alina each sang either or times. If denotes the number of songs sung by trios, then or or . Since the girls sang as trios, the total must be a multiple of . Only qualifies. Therefore, is the number of songs the trios sang.
Challenge: Devise a schedule for the four girls so that each one sings the required number of songs.