Question

Using the ready reckoner, find the period of interest for an amount equals to $Rs.16,939.2$, Principal $Rs.12,000$ at $9\%$ p.a.

Answer 1

Given : $P=12,000$ Rs., $R=9\%$ and amount $A=16,939.2$

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

$⟹16939.2=12000{(1+\frac{9}{100})}^n$

$⟹\frac{16939.2}{12000}={\left(\frac{109}{100}\right)}^n$

$⟹1.4116=(1.09{)}^n$

$⟹(1.09{)}^4=(1.09{)}^n$

$⟹n=4$ years

Hence, the period of interest will be $4$ years.