Ryan is self-employed. This year Ryan used his personal auto for several long business trips. Ryan paid $2,190 for gasoline on these trips. His depreciation on the car if he was using it fully for business purposes would be $3,600. During the year, he drove his car a total of 21,100 miles (a combination of business and personal travel).

a. Ryan can provide written documentation of the business purpose for trips totaling 4,220 miles. What business expense amount can Ryan deduct (if any) for these trips?

b. Ryan estimates that he drove approximately 2,315 miles on business trips, but he can only provide written documentation of the business purpose for trips totaling 1,350 miles. What business expense amount can Ryan deduct (if any) for these trips?