I need help on this tax question

Question 2 (10 points) Verlin sells a commercial building and receives $50,000 in cash and a 5 year note for $75,000/year payable at 10% interest. Verlin's adjusted basis in the building on the date of sale is $40,000 and he collects only the $50,000 down payment in the year of the sale. a. If Verlin elects to recognize the total gain on the property in the year of sale, calculate the taxable gain. b. Assuming Verlin uses the installment sale method, calculate the taxable gain he must report for the year of the sale. c. Assuming Verlin uses the installment sale method, calculate the taxable gain he must report in the year after the sale