Mary starts from her house, walks 80 meters south, and stops to chat with her aunt on the sidewalk. after chatting for a few minutes, she walks 125 meters to the west to meet a friend and then walks 45 meters north with her friend to a café for lunch. overall, she takes 10 minutes to do all of this. what is mary's average speed? a) 8 m/s b) 1.25 m/s c) 25 m/s d) 4.5 e) 0.42

E is the correct answer because you have to multiply 10 by 60 (60 seconds in a minute) before doing distance over time. you also have to add all the distances up before this. 
60*10=600
125+80+45=250
so, 250/600= .416666 
=E

W= fd
where f is an applied force and d is the distance over which it is applied. when a parachuting skydiver is at constant velocity, he is experiencing "terminal velocity", the point at which his acceleration down is canceled out by air resistance. that means that the resisting force of the air is equal to his weight, but in the opposite direction. with this, we can solve for the work done by the force.
w = fd
w = (92.0)(9.81 m/s^2) (325)
w= 2.93 x 10^5 j
the value for work in this case is positive because it is pushing up on the skydiver, who has a downward force of gravity.
therefore the answer is 2.93 x 10^5 j