A sum was put at simple interest at a certain rate for 3 years. Had it been put at 1% higher rate, it would have fetched Rs. 5100 more. The sum is

1Rs. 1, 20, 000
2Rs. 1, 25, 000
3Rs. 1, 50, 000
4Rs. 1, 70, 000

Answer:- 1

Explanation:-

Solution:

\begin{aligned} Let the sum be Rs . x and \\ original rate be R % \\ Then, \\ \Rightarrow \frac{x \times (R + 1) \times 3}{100} - \frac{x \times R \times 3}{100} = 5100 \\ \Rightarrow 3 R x + 3 x - 3 R x = 510000 \\ \Rightarrow 3 x = 510000 \\ \Rightarrow x = 170000. \\ Hence, \\ Sum = Rs .170000 . \end{aligned}

$\eqalign{ & {\text{Let the sum be Rs}}{\text{. }}x{\text{ and}} \cr & {\text{original rate be R}}\% \cr & {\text{Then,}} \cr & \Rightarrow \frac{{x \times \left( {{\text{R}} + 1} \right) \times 3}}{{100}} - \frac{{x \times {\text{R}} \times 3}}{{100}} = 5100 \cr & \Rightarrow 3{\text{R}}x + 3x - 3{\text{R}}x = 510000 \cr & \Rightarrow 3x = 510000 \cr & \Rightarrow x = 170000. \cr & {\text{Hence,}} \cr & {\text{Sum}} = {\text{Rs}}.170000. \cr}$