Give an example of an addition problem in which you would and would not group the addenda differently to add

Which of the following questions is a statistical question? (2 points) how many professional sport leagues are there? where do the professional sport leagues play? how many hours of professional training took place over the weekend? how many hours do you spend each week training for a sports league?

Two planes leave an airport at the same time, one flying east, the other flying west. the eastbound plane travels 20 mph slower. they are 1600 mi apart after 2 hr. find the speed of each plane.

If 30 lb of rice and 30 lb of potatoes cost ? $27.60? , and 20 lb of rice and 12 lb of potatoes cost ? $15.04? , how much will 10 lb of rice and 50 lb of potatoes? cost?