The temperature in sweden was -3 at 3pm after 6 hours the temperature dropped to -15 the temperature dropped the same amount each hour what was the change in temperature each hour

Can someone me out here and the tell me the greatest common factor

You give a $4 tip for a meal that cost $22. approximately what percent of the bill was your tip?

Acar started driving from city a to city b, distance between which is 620 miles, at a rate of 60 mph. two hours later a truck left city b and started moving towards city a at a rate of 40 mph. what distance from city a is the point where the truck and the car will meet?