Question

a sum amounts rupees 1326 in 6 year at 5% per annum simple interest in what time will the sum double itself at the same rate of interest

Answer 1

amount=1326
time =6 yrs
rate= 5%p.a
amount-principal=(p×r×t)/100
(1326-p)×100=p×5×6
{(1326-p)×100}=30p
30p=132600-100p
30p+100p=132600
130p=132600
p=132600/130
p=₹4420
let time be t
as most doubles itself then
amount= 2×₹4420
=₹8840
,rate=5% p.a
si=₹(8840-4420)
=₹4420
4420=(4420×5×t)/100
(4420×100)/(4420×5)=t
t=20 yrs
money will double itself in 20 yrs