Question

Using the ready reckoner, find the rate of interest on compound interest as $Rs.1,733.6$ for $3$ years on principal of $Rs.11,000$.

Answer 1

Given : $P=11,000$ Rs., $n=3$ and C.I. $=1,733.6$

Amount $A=P{(1+\frac{R}{100})}^n$

Compound interest for on Rs. $11,000$ is $1,733.6$

Therefore, Compound interest for on Rs. $1$ is $=\frac{1733.6}{11000}=0.1576$

Now, C.I. $=A-P$

$⟹A=C.I.+P$

$=0.1576+1=1.1576$

$⟹1.1576=P{(1+\frac{R}{100})}^n$

$⟹1.1576={(1+\frac{R}{100})}^3$

$⟹1.04999=1+\frac{R}{100}$

$⟹0.04999=\frac{R}{100}$

$⟹R=4.999$

$⟹R=5\%$

Thus, the rate of interest for $11,000$ will be $5\%$.

Hence, the rate of interest is $5\%$.