Question

if the amount of Rs. 400/- for 2 years is 441 then find the annual rate of compound interest​

Answer 1

Solution :

$\underline{\bf{Given\::}}}}$

• Principal, (P) = Rs.400
• Amount, (A) = Rs.441
• Time, (n) = 2 years

$\underline{\bf{Explanation\::}}}}$

Using formula of the compounded annually :

$\boxed{\bf{Amount=Principal\bigg(1+\frac{R}{100} \bigg)^{n} }}}}$

$\longrightarrow\sf{441=400\bigg(1+\dfrac{R}{100} \bigg)^{2} }\\\\\\\longrightarrow\sf{\dfrac{441}{400} =\bigg(1+\dfrac{R}{100} \bigg)^{2} }\\\\\\\longrightarrow\sf{\sqrt{\dfrac{441}{400} } =1+\dfrac{R}{100} }\\\\\\\longrightarrow\sf{\dfrac{21}{20} =1+\dfrac{R}{100} }\\\\\\\longrightarrow\sf{\dfrac{21}{20} -1=\dfrac{R}{100} }\\\\\\\longrightarrow\sf{\dfrac{21-20}{20} =\dfrac{R}{100} }\\\\\\\longrightarrow\sf{\dfrac{1}{20} =\dfrac{R}{100} }\\\\\longrightarrow\sf{20R=100}$

$\longrightarrow\sf{R=\cancel{100/20}}\\\\\longrightarrow\bf{R=5\%}$

Thus;

The rate of the Interest will be 5% .

Answer 2

Answer:

please see number c

rate of interest is 5%

hope it helped you