Question

A person deposited 100 rupees in a Bank and received 121 rupees as the amount
after 2 years. The rate of compound interest per annum is_________​

Answer 1

Answer:

let the rate of compound interest is x%

so after 1 year interest =Rs100.x/100 =Rs x

after 1 year amount Rs(100+x)

after two year interest = Rs(100+x).x/100

after 2 year amount=Rs {(100+x)+(100+x).x/100}

so,

(100+x)+(100+x).x/100=121

=> 100(100+x)+x(100+x)=121×100

=>( 100+x) (100+x)=121×100=12100

=> (100+x)^2=(110)^2

=> 100+x=110

=> x=110-100

=> x=10

so rate of compound interest per annum is 10%

Answer 2

Answer:

10%

Step-by-step explanation:

we know formula

A=p (1+r/100)^n

121=100(1+r/100)^2

1.21=(1+r/100)^2

( 1.1)^2=(1+r/100)^2

take square root in both side

1.1=1+r/100

r=10%

rate is 10%

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