Two hundred fence posts are to be placed into the ground in a straight line, 5m apart. The fence posts are stacked in a pile along this same line, 5 m from the position of the first post to be put in. Maybell is going to put inthe posts one at a time in order, and each post she puts in is farther away from the pile. Maybell can only carry one post at a time, and so she always walks back to the pile to getthe next post. If Maybell starts at the pile, how many kilometers must she walk to finish the job?
+37146 1st post walks 5 m + 5 m = 10m
2nd post walks 10m + 10m = 20
Arithmetic sequence d = 10 a1=10 a200 = 2000
sum n(a1+a200)/2 = 200 (10+2000)/2 = 201000 In reality, she doesn't need to walk back after the last post is placed
so subtract 1000 200 000 = 200 km
