It cost raquel $5 in tolls to drive to work and back each day, plus she uses 3 gallons of gas. it costs her a total of $15.50 to drive to work and back each day. how much per gallon is raquel paying for her gas? how do you know?

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)