Question

A sum of Rs. 800 would become Rs. 882 after 2 years at r% compound interest, find the
value of 'r:​

Answer 1

Step-by-step explanation:

here simple interest is principal-amount

s.i = 800-882=82

R%= si*100/p*t

82*100/800*2

therefore R = 5.1%

Answer 2

Answer

Step-by-step explanation:

A = P [ 1+R/100 ] ^n

882 = 800 [ 1+R/100 ] ²

• Now, transposing [ 1+R/100 ] ² to LHS

[ 1+R/100 ] ² = 882/800

[ 1+R/100 ] ² = 441/400

1+R/100 =

$\sqrt{441 \div 400}$

In LHS, square will transfer to RHS then it becomes square root of it:-

1+R/100 =

$\sqrt{21 \div 20}$

Because 441 and 400 are perfect squares

Now, we should take LCM of [ 1+R/100 ]

$\frac{100 + r}{100} = \frac{21}{20}$

{ r = R}( which is Rate )

$100 + r = \frac{21}{20} \times 100$

• Transposing 100 from LHS to RHS

$100 + r = 21 \times 5$

$100 + r = 105$

$r = 105 - 100$

• Transposing 100 from LHS to RHS

So, therefore,

R = 5%

Hope, it helps u