A certain sum (in ₹)is invested at simple interest at x% p.a. for 5 years. Had it been invested at (x + 5)% p.a., the simple interest would have been ₹9,200 more than the earlier one. Whatis the sum?

We know that simple interest (SII)=  $$\dfrac{PRT}{100}$$

where P = principle , R= rate , t = time

According to question Simple intrest (SI) = $$ \dfrac{Px5}{100} $$ (let Rate = $$x$$)......... equestion  (1)

2nd condition $$ Simple intrest (SI)  + 9200= \dfrac {P (x+5) 5}{100} $$ ......... equestion (2)

then equestion (2) - equestion (1) 

$$ \Rightarrow 9200 = \dfrac {P \times 5 \times 5} {100}$$

 P = $$9200 \times 4 $$

$$ P= Rs 36800 $$Ans