Let the principal, rate of interest and time at which sum will become6 times be ₹ P, r% p.a. and n years,respectively.
∴3P=P+
P×r×5
100
(A=P+SI)
⇒r=
2×100
5
=40 Now,6P=P+
P×40×n
100
⇒n=
5×100
40
=12.5 years Trick : Suppose you have deposited ₹100 in bank. Then in five years, it will become ₹300 and in the next 5 years, it will become ₹500 and in the next 2.5 years, it will become ₹600, which is 6 times of principal. So, total time