if a sum of money grows to 144/121 times when invested for 2 years in a scheme where the interest is compounded annually ,then how long will the...

The principle P becomes 144/121 times in 2 years in a
compound interest annual.

Therefore  P(144/121) =
P(1+r)^2

144/121 = (1+r)^2.

We
take square root.

12/11 =
1+r

12/11 -1 = r

r =
(12-11/)11 = 1/11.

Therefore (100/11)% is the rate of
annual interest.

So for n years the simple interest =
Pnr/100 = Pn (100/11)/100 = Pn/11.

So along wirh principle
and the interest ,the amount  P+Pn/11

If it takes n years
to triple the ampount , 3P = P+Pn/11

3 =
1+n/11

n/11 = 3-1=2

n = 2*11 =
22.

Therefore it takes 22 years for the Principle along
with a simple interest of (100/11)% PA to become 3 times
itself(principle)