Answer:
Remaining balance = AED 13.75
Explanation:
Given that:
Amount of gift card = AED 20 
Amount left after buying 3 songs = AED 16.25 
Cost of 3 songs = 20 - 16.25 = AED 3.75
Cost per song = 

Cost per song = AED 1.25 
Cost of 5 songs = 5(1.25) = AED 6.25 
Remaining balance = 20 - 6.25 = AED 13.75
Hence, 
Remaining balance = AED 13.75