A farmer wishes to fix fencing rails to posts which are already in place. The posts are shown in the diagram. The farmer has a supply of rails, each one 2.4 m long. One rail or part of a rail is to be fixed between each pair of posts. (He can cut the rails into smaller lengths.)
What is the smallest number of rails that he could use?
A. 5
B. 3
C. 4
D. 6
E. 7
To find the smallest whole number of rails needed, we will first have to find the exact amount of rails needed to fix the fence, then round it up.
To do so, we have to divide the total distance between the posts by the length of one whole rail. So:
( 115+ 90 + 120 + 180 + 210 + 150 +210 ) / 240 = 4.48
Now we round up the amount of rails needed to the next whole number.
4.48 → 5
Therefore, the answer is A