Question

A sum of money becomes four times itself
in 9 years under simple interest. In how
many years will it become 22 times itself?​

Answer 1

Let sum=x

We know,
S.I.=
100
PRT
​


SI=x

Rate=
(x×6)
(100×x)
​

=
3
50
​
%

Now sum =x, S.I=3x
Rate=
3
50
​
%

Time
=
x×
3
50
​

(100×3x)
​

=18 years.