Question

Sanjay invested an amount of rs.16000 for two years on compound interest and received an amount of rs 17640 on maturity what is the rate of interest per annum?​

Answer 1

Answer:

P=16000 ,A=176400 ,T=2years

Let rate be R%

A=P(1+

100

R

)

T

17640=16000(1+

100

R

)

2

16000

17640

=(1+

100

R

)

2

=>(

40

42

)

2

=(1+

100

R

)

2

=>

40

42

=1+

100

R

=>

100

R

=

20

21

−1

=

20

1

=>R=

20

100

=5%

Hence, Rate%=5%pa

Answer 2

$\huge\mathfrak{Answer}$

$\huge \boxed{ \rm \sf \frac{a}{p} = {1 + \frac{r}{100} }^{n}}$

$\huge \boxed{ \rm \sf \frac{17640}{16000} = {1 + \frac{r}{100} }^{2}}$

$\boxed{ \rm \sf \frac{17640}{16000} = {1 + \frac{r}{100} }^{2}} \implies { \frac{21}{20} }^{2}$

OR

$\sf \boxed{1 + \frac{r}{100} } = \frac{21}{20} \\ \\ \therefore \sf \: rate \: \: = 5\%$

5% is the answer