A sum of Rs. 8,400 amounts to Rs. 11,046 at 8.75% p.a. simple interest in a certain time. What will be the simple interest (in Rs.) on a sum of Rs. 10,800 at the same rate for the same time?

$$\eqalign{ & {\text{A}} = {\text{P}} + {\text{S}}{\text{.I}}{\text{.}} \cr & {\text{S}}{\text{.I}}{\text{.}} = \frac{{{\text{P}} \times {\text{R}} \times {\text{T}}}}{{100}} \cr & 11046 = 8400 + \frac{{8400 \times 8.75 \times {\text{T}}}}{{100}} \cr & 2646 = \frac{{84 \times 875 \times {\text{T}}}}{{100}} \cr & 2646 = 21 \times 35 \times {\text{T}} \cr & {\text{T}} = 3.6{\text{ years}} \cr & {\text{S}}{\text{.I}}{\text{.}} = \frac{{10800 \times 8.75 \times 3.6}}{{100}} \cr & = \frac{{108 \times 875 \times 36}}{{1000}} \cr & = 3402 \cr} $$