Question

The breadth of a rectangular field is 15 m. The length of the rectangular
field is 3 times as long as its breadth. Each metre of fence costs $4. How
much will it cost to fence the field?

Answer 1

Breadth=15m

Length=3×breadth

=45m

Therefore, the perimeter=2(l+b)

=2×60

=120m

Cost of fencing 1m=$4

" " " 120m=120×4

=480

Therefore,cost of fencing it would be$480

Answer 2

$breadth = 15m \\ length = 3times \: its \: breadth \: \\ \: \: \: \: \: \ \: \: \: \: \: \: \: \: \:= 3 \times 15 \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \ \: = 45m \\ perimeter \: of \: rectangular \: field \: = 2(l + b) \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 2(15 + 45) \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \:= 120m \\ fence \: cost \: per \: meter \: = 4 \\ cost \: of \: 120m = 4 \times 120 \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 480$