Question

a sum of money doubles itself in 3 years at compound interest, when the interest is compounded anually. In how many years will it amount to 16 times of itself?

a)6years
b)8years
c)12years
d)16years​

Answer 1

Answer:

12  yrs

Step-by-step explanation:

let the sum of money be x

let the rate of interest be y

then ,  x ( 1+ y/100) ^3 = 2x

=  ( 1+ y/100)^3 = 2x/x

= ( 1 + y/100)^3 = 2

=   ((1 + y/100) ^3)^4 = (2)^4   , ( becoz 2^4 = 16)

=  ( 1 + y/100 )^12  = 16

Hence it will take 12 yrs  , and do mark my answer as brainliest if you found it helpful.