A rectangular plot measuring 90 metres by 50 metres needs to be enclosed by wire fencing such that poles of the fence will be kept 5 metres apart. How many poles will be needed?
30
44
56
60
Explanation:
Perimeter of a rectangle = 2(l + b)
where l is the length and b is the breadth of the rectangle
Length of the wire fencing = perimeter = 2(90 + 50) = 280 metres
Two poles will be kept 5 metres apart. Also remember that the poles will be placed along the perimeter of the rectangular plot, not in a single straight line which isvery important.
Hence number of poles required = $\dfrac{280}{5}$ = 56