Answer:
28 posts of 60 cm length can be cut from a log 17 m in length, with 0.333 m of the log left over.
Explanation:
The log is 16 ± 1 meters long. Fence posts are 70±10cm long.
The greatest number of fence posts that could possibly be cut from the log would occur if the larger number for the log length (17 m) would also happen to coincide with the shortest post length (60 cm). This seems unlikely, but the question says "can possibly be cut." This unlikely combination of lenghts is a possible event, so lets use it.
60 cm is 0.60 meter. (100cm/meter)
Divide the total log length by the length per post to find posts/log:
(17 meters)/(0.60 meters) = 28.333 . . .
0.333 . . . is not a post. So 28 posts of 60 cm length can be cut from a log 17 m in length.