What equal installment of annual payment will discharge a debt which is due as Rs. 848 at the end of 4 years at 4% per annum simple interest ?

Answer: Option A

Let the annual installment be Rs. x.
Then,
$$\Rightarrow \left[x+\left(\frac{x\times 3\times 4}{100}\right)\right]+$$     $$\left[x+\left(\frac{x\times 2\times 4}{100}\right)\right]+$$     $$\left[x+\left(\frac{x\times 1\times 4}{100}\right)\right]+$$     $$x=848$$
$$\begin{array}{rl}& \iff \frac{28x}{25}+\frac{27x}{25}+\frac{26x}{25}+x=848\\ & \iff 106x=848\times 25\\ & \iff 106x=21200\\ & \iff x=200\end{array}$$

Short Cut Method : The annual payment that will discharge a debt of Rs. A due in t years at the rate of interest r % p.a. is.
$$\begin{array}{rl}& \frac{100\text{A}}{100t+\frac{rt\left(t-1\right)}{2}}\\ & \therefore \text{Annual installment}\\ & =\text{Rs}\text{.}\left[\frac{100\times 848}{100\times 4+\frac{4\times 4\times 3}{2}}\right]\\ & =\text{Rs}\text{.}\left(\frac{100\times 848}{424}\right)\\ & =\text{Rs}\text{. }200\end{array}$$