The area of a rectangular field is 2100 sq. metres. If the field is 60 metres long, what is its perimeter? (Bank Recruitment, 2007)

### Concept & Formula The perimeter requires both length and breadth. First, deduce the missing dimension (breadth) using the area formula, then apply the perimeter formula. $$ \text{Area} = L \times B $$ $$ \text{Perimeter} = 2(L + B) $$ ### Step-by-Step Solution * **Given:** $\text{Area} = 2100\text{ sq. m}$, Length ($L$) = $60\text{ m}$. * **Step 1:** Find the breadth ($B$). $2100 = 60 \times B$ $B = \frac{2100}{60} = 35\text{ m}$ * **Step 2:** Calculate the perimeter. $\text{Perimeter} = 2 \times (60 + 35)$ $\text{Perimeter} = 2 \times (95)$ $\text{Perimeter} = 190\text{ m}$ ### Exam Strategy & Shortcut When you calculate the perimeter as $190\text{ m}$ and scan the options, you'll notice $190\text{ m}$ is missing. Do not second-guess your calculation if you are confident; simply select "None of these". ### Common Pitfall A frequent error is calculating the breadth ($35\text{ m}$) and inadvertently searching for that number in the options, or forgetting to multiply the sum of length and breadth by $2$ for the perimeter. ### Final Answer Therefore, the correct answer is **None of these**.