Question

In what time will₹1200 amounts to ₹1323 at 5% compound interest???

Answer 1

Principal = Rs. 1200; A = Rs.1323; R = 5%; N = ? 

1323=1200(1+5/100)^n

(1323/1200)=(105/100)^n

(441/400)=(21/20)^n

(21/20)^2=(21/20)^n





Number of years

n= 2

Answer 2

Answer:  The required time is 2 years.

Step-by-step explanation:  We are given to find the time in which Rs. 1200 amounts to Rs. 1323 at the rate of 5% compound interest.

Let the required time be n years.

Also, P = Rs. 1200, A = Rs. 1323  and  r% = 5%.

According to the given information, we have

$A=P\left(1+\dfrac{r}{100}\right)^n\\\\\\\Rightarrow 1323=1200\left(1+\dfrac{5}{100}\right)^n\\\\\\\Rightarrow \dfrac{1323}{1200}=\left(1+\dfrac{1}{20}\right)^n\\\\\\\Rightarrow \dfrac{441}{400}=\left(\dfrac{21}{20}\right)^n\\\\\\\Rightarrow \left(\dfrac{21}{20}\right)^2=\left(\dfrac{21}{20}\right)^n\\\\\\\Rightarrow 2=n\\\\\Rightarrow n=2.$

Thus, the required time is 2 years.