₹8,000 becomes ₹9,800 in three years at simple interest rate. If the rate of interest becomes two times of itself, then what will be the amount of the same principle in four years?

Correct option is C

$SI=A-P=₹9,800-₹8,000=₹1,800$

$$\text{SI} = \frac{P \times R \times T}{100}$$

$$\text{1800} = \frac{8000 \times R \times 3}{100}$$

R= 7.5% 

When the interest becomes doubled = 2 times of 7.5% = 15% 

New SI= $$= \frac{8000 \times 15 \times 4}{100}$$ = Rs. 4800

Final Amount = 4800+ 8000 = Rs. 12800