You own and are preparing to fly a small airplane. You have just performed an engine oil change, which is listed as preventive maintenance in 14 CFR part 43, Appendix A. To comply with FAA regulations, what must you do?

A private pilot performed an oil change, which is preventive maintenance, when the tachometer read 2,345.6 hours. Oil changes are required every 50 hours of operation. The current tachometer reading is 2,385.0 hours. How many hours remain before the next oil change is due?