They decide to save money going to Kelowna and can leave tonight by bus. They need to get back to the high school for a sporting event so will take the express train where they can save three hours of travel time because the express train travels 25 km/h faster than the bus. If the distance between South Central High and Kelowna is 1500 km, determine how long it will take to travel in total if they travel by bus going to the conference and then by express train coming back from the conference, rounded to the nearest hour. a-12 hours
b-27 hours
c-15 hours
d-30 hours