Question

calculate the rate of interest if ₹8000 amounts to ₹10,648 in 3 years at compound interest.

Answer 1

p= 8000
t=3 years
A= 10648

C = A-P
C = 10648- 8000
= 2648
$a = p(1 + \frac{r}{100} ) {}^{3}$
10648 = 8000( 1 + r/100)^3

10648/8000 = ( 1+ r/100)^3

1331/1000 = ( 1+ r/100)^3

11/10 = 1+ r/100

11/10 -1 = r/100

(11 -10)/10 = r/100

1/10 = r/100

100 = 10r

100/10 = r

10% = r or r = 10%

hope it is clear to you

Answer 2

p= 8000
t=3 years
A= 10648

C = A-P
C = 10648- 8000
= 2648

10648 = 8000( 1 + r/100)^3

10648/8000 = ( 1+ r/100)^3

1331/1000 = ( 1+ r/100)^3

11/10 = 1+ r/100

11/10 -1 = r/100

(11 -10)/10 = r/100

1/10 = r/100

100 = 10r

100/10 = r

10% = r or r = 10%

hope it is clear to you