You and a friend start biking in opposite directions from the same point. you travel 108 feet every 8 seconds. your friend travels 63 feet every 6 seconds.
to the nearest hundredth of a mile, how far apart are you and your friend after 15 minutes?

63= 60 then... 60/6 = 10
108=100 then... 100/ 8= 12. 5 
60 sec in 1 min so ...
12.5 * 6 =  75
10*6= 60 
75 - 60= 15 feet apart.

A decagon has 10 sides. If the polygon is symmetrical, the angle of rotation is given by the following equation:

360 / (number of sides)

Therefore, 

360 = 10 = 36.

The interior angles are determined by the following equation:

180 - (angle of rotation)

Therefore, 

180 - 36 = 144

The answer is A.