first, how much were her songs? It's two songs each, and their separate prize was 0.99:
total prize was 2*0.99=1.98
this gets added to the membership prize:
19.99+1.98=21.97
you can also calculate this by rounding all the numbers (20+1+1) and substracting the amount you rounded (three times one cent) - the result would be the same.