400
When he turned on the car this morning Mr. Stephenson's car gave him a low tire pressure warning, at 26 psi (1.8 atm). He drove to school any way because there was a pep rally, and when he arrived the temperature was 18 degrees Celsius and his tires were now measuring 31 psi (2.1 atm). Give the outside temperature in Kelvin when he left the house.
What is 249k?