Question

The compound interest on a certain sum for $1$ year at $5\%$ per annum is Rs. $1680$, find the simple interest on the same sum for $1$ years at $5\%$ per annum

• A. Rs. $800$
• B. Rs. $1810$
• C. Rs. $1680$
• D. Rs. $1560$

Answer 1

The correct option is C Rs. $1680$

$\Rightarrow$ We have given, Compound interest = Rs.1680 and R = 5%

$\Rightarrow$ We know that, $Compoundinterest=A-P$

$\Rightarrow$ $1680=P(1+\frac{R}{100})-P$

$\Rightarrow$ $1680=P[1+\frac{5}{100}-1]$

$\Rightarrow$ $P=\frac{1680\times 100}{5}$

$\therefore$ $P=Rs.33,600$

$\Rightarrow$ For simple interest $R=5\%$ and $P=Rs.33,600$

$\therefore$ $Simpleinterest=\frac{P\times R\times T}{100}$

$\Rightarrow$ $Simpleinterest=\frac{33600\times 5\times 1}{100}=Rs.1680$