A freight train from city a to city b and a passage train from city b to city a left the cities at the same time, at 10:00 am heading towards each other. The distance between the cities is 360 miles. The freight train is traveling at 50 mph the passages train is traveling at 70 mph. What time will the trains pass each other

The weight of a radioactive isotope was 96 grams at the start of an experiment. after one hour, the weight of the isotope was half of its initial weight. after two hours, the weight of the isotope was half of its weight the previous hour. if this pattern continues, which of the following graphs represents the weight of the radioactive isotope over time? a. graph w b. graph x c. graph y d. graph z