What is the mean of the given data set?

The number of calories you burn depends on your weight. a 110-pound person burns 163 calories during 30 minutes of tennis. find the number of calories that a 190-pound person would burn during the same activity, assuming they burn calories at the same rate.

Grading scale 1 has the following weights- (tests- 50% quiz- 25% homework- 15% final exam- 10%). calculate your final average if your performance in the class is as follows-test grades- {88, 84, 90, 75, 70, 81); quiz grades- {88, 67, 90, 90, 45, 99, 76, 98, 100}; homework- 90; final exam- 75

If a and b are real numbers, then |a-b| is always, sometimes or never equal to |b-a| ?