A bus and a car leave from the same city traveling in opposite directions. The bus leaves 2 hours before the car does. The bus travels at a steady speed of 50 mph while the car travels at 70 mph. After how many hours will the bus and car be 800 miles apart? If h represents the number of hours the bus travels, then which of the following expressions represents the number of miles the car travels?

Anew test for ra is being developed. the test is administered to 750 patients with ra and 750 without ra. for the sake of the question, assume the prevalence of ra in this population is 50%. of the 750 patients with ra, 575 have a positive result. of the 750 patients without ra, 150 have a positive result. what is the positive predictive value of the new test? a575/(575+150) b. 600/(600+ 150) c. 575/(575+125) d. 600/(600+ 125)