Question

The cost of fencing a rectangular field at Rs 30 per metre is Rs 2400. If the length of the field is 24 m, then its breadth is
(a) 8 m
(b) 16 m
(c) 18 m
(d) 24 m

Answer 1

(b) 16 m
Total cost of fencing = Rs 2400
Rate of fencing = Rs 30/m
Perimeter of the rectangular field = $\frac{\mathrm{Total}\mathrm{cost}}{\mathrm{Rate}}=\frac{\mathrm{Rs}2400}{\mathrm{Rs}30/\mathrm{m}}=80\mathrm{m}$
Let the breadth of the rectangular field be x m.
Perimeter of the rectangular field = 2(24 + x) m
$$\begin{gathered} \Rightarrow 2(24+x)=80 \\ \Rightarrow 48+2x=80 \\ \Rightarrow 2x=(80-48) \\ \Rightarrow 2x=32 \\ \Rightarrow x=\frac{32}{2}=16 \\ \mathrm{So},\mathrm{the}\mathrm{breadth}\mathrm{of}\mathrm{the}\mathrm{rectangular}\mathrm{field}\mathrm{is}16\mathrm{m}. \end{gathered}$$