Question

Using the ready reckoner, find the rate of interest for an amount equal to $Rs.35,246$, Principal $Rs.20,000$ for $5$ years.

Answer 1

Given : $P=20,000$ Rs., $n=5$ and $A=35,246$

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

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

$⟹C.I.=35246-20000=15,246$

Compound interest for on Rs. $20,000$ is $15,246$

Therefore, Compound interest for on Rs. $1$ is $=\frac{15246}{20000}=0.7623$

From $\left(i\right)$

$⟹1.7623=P{(1+\frac{R}{100})}^n$

$⟹1.7623={(1+\frac{R}{100})}^5$

$⟹1.1199=1+\frac{R}{100}$

$⟹0.1199=\frac{R}{100}$

$⟹R=11.99$

$⟹R=12\%$

Hence, the rate of interest is $12\%$.