Disposal of asset

Hi. This question is from the Kaplan Study text (Appendix 1: Published Financial Statements - TYU 3) My doubt is on how the profit on disposal of $100 was calculated. I hope you can help me understand. The relevant information: ".... During the year Marlon sold some catering equipment for $2500. This related to equipment that originally cost $5000 and had been depreciated by $2600. No entries have been made at all in the trial balance for this disposal" I hope this is enough information. Thank you so much!