+rental income 40k
-tax 16k
-repair 5k + 5k (when you vacate tenant to sell, prepared for some repairs)
-insurance 2k
-interest 12k
-mortgage closing cost 5k
-selling cost 18k
+selling gain 50k
total 90k-63k=27k on capital investment of 55k initial cash expenses, or 25% ROI rate.