If a car travels at a speed of 25 mi/h for t hours, then travels 45 mi/h for m hours, what does the expression 25t + 45m represent?

M∠abc=138° and m∠def=31° . which statement is true about ∠abc and ∠def ? a: the angles are neither complementary nor supplementary. b: the angles are complementary. c: the angles are supplementary.