If Rs. 2800 is 2/7 percent of the value of a house, the worth of the house (in Rs.) is :

Answer: Option B

Let the worth of the house be Rs. x
Then,
$$\frac{2}{7}$$% of x = 28000
$$\begin{array}{rl}& \Rightarrow \left(\frac{2}{7}\times \frac{1}{100}\times x\right)=2800\\ & \Rightarrow x=\left(\frac{2800\times 100\times 7}{2}\right)\\ & \Rightarrow x=980000\end{array}$$