Answer:
10 songs
Step-by-step explanation:
Based on the scenario being described we seem to need to find the greatest common multiple of these two bands. This is done simply by multiplying the songs in each set of each band by every factor (1 2 3 4 5 ...) until you find a common product between each band. Like so...
5*1 = 5 10*1 = 10
5*2 = 10
We can see that the first and smallest number of songs that each band could have performed would be 10 songs. Meaning that Lily's Band played two (2) sets and Dustin's Band played one (1) set.