t 2 4 6 8 10 12

Question

v(t) 44 42 41 40 37 35

the velocity in the table is decreasing 2 </= x </= 12. Using n=5 subdivisions, approximate the total distance traveled for:

a) an upper estimate
b) a lower estimate

i'm not quite sure what the question is asking. i don't understand how n=5 fits in the approximation.