What is percent of change $50 to $65

You would do percent of change.
meaning you would subract 65 and 50 to get 15. then you would put 15 over 50 (as a fraction) then equals r/100. then you would cross multiply to get r.

orginal:50
new:65
65-50=15

15/50=r/100
15r=5000
then divide by 15 to get r

Yes you do, so £1973.09 - £1473.50 = £499.59 so tim overpaid £499.59 .hope this ; )