RRB Paramedical Staff Nurse Model Paper 6

Here, ${\mathit{R}}_1={\mathit{R}}_2=5\%{\mathit{T}}_1=4\mathit{y}\mathit{r}{\mathit{T}}_2=3\mathit{y}\mathit{r}$
According to the question,
$\Rightarrow \frac{\mathit{P}\times 5\times 4}{100}-\frac{\mathit{P}\times 5\times 3}{100}=42$
$\Rightarrow \frac{\mathit{P}}{5}-\frac{3\mathit{P}}{20}=42$
$\Rightarrow 4\mathit{P}-3\mathit{P}=42\times 20$
Thus, $\mathit{P}=\mathrm{Rs}840$
Alternate Method
If is the difference of interest obtained from two sources on Rs P int yr be Rs $\mathit{x}$. then the difference in rates of interest will be
$\mathit{R}=\frac{\mathit{x}\times 100}{\mathit{P}\times \mathit{t}}$
SI for $1\mathit{y}\mathit{r}=\mathrm{Rs}42=\mathit{x}$
Then,
Thus, Principal