Question

At what rate per cent will the compound interest does a sum of money becomes four fold in 2 yr

(a).75%
(b).100%
(c).150%
(d).200%
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Answer 1

Answer:

let principal be x

then amount=4x

time=2 yrs

therefore

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

or, 4x=x(1+r/100)^2

or, 4=(1+r/100)^2

or, 2^2=(1+r/100)^2

therefore,

1+r/100=2

or, r/100=2-1

or, r/100=1

or, r=1×100

∴r=100

answer is (b)100%

Step-by-step explanation: