Verified Answer :

100 - 20 = 80%

$52 represents 80% of the original price of the MP3 player.

13 represents 20% of the original price of the MP3 player.

13 * 5 = $
65
20 5 = 100%

The original price of the MP3 player was $65.

Check:

65
0.2 = 13
65 - 13 = 52