Verified Answer :

alber

The answer is fairly simple. Each week they sing 8 songs, and so in 5 weeks they would sing 8x5 songs (which is 40) in 6 weeks, they would sing 8x6 songs (which is 48) and in 7 weeks 7x8 songs (which is 56)

5 weeks = 40 

6 weeks = 48

7 weeks = 56