fence?看不懂.6.Astraightfenceistobeconstructedfromposts6incheswideandseparatedbylengthsofchain5feetlong.Ifacertainfencebeginsandendswithapost,whichofthefollowingcouldbethelengthofthefenceinfeet?(12inches=

Question

fence?看不懂.
6.A straight fence is to be constructed from posts 6 inches wide and separated by lengths of chain 5 feet long.If a certain fence begins and ends with a post,which of the following could be the length of the fence in feet?(12 inches = 1 foot).
Indicate ALL such answers.
A.17
B.28
C.35
D.39
E.50
Correct Answer:ABDE
Explanation:
The fence will consist of one more post than there are chains.(e.g.P-c-P-c-P).
Therefore,a total length has to be a multiple of the length of the chain plus one post (5.5) plus one post extra.We have length = (5.5n + 0.5),where n can be any positive whole number.If n= 3,length =17; if n= 5,length = 28,etc.but there is no whole number that can give 35.Hence all the answers except C are correct.

Answer 1

fence是栅栏、篱笆、围墙的意思,
在这道题里面,是说栅栏每隔5英尺就需要一个6英寸（0.5英尺）的栅栏柱（post,这里是柱或者桩的意思）来连接,同时栅栏的头尾都必须是柱.
所以长度可以得出是5.5n + 0.5