A person has set up a sinking fund so that he can accumulate Rs 100000 in 10 years for his children's higher education. How much amount should he deposit every six months if interest is 5% per annum compounded semi-annually ?
Answer & explanation
Correct answer: option 1
The correct answer is option (1) : ₹3924.64
Given $A= ₹10000$
$r=\frac{5}{2}$% per half year
$i=\frac{2.5}{100}=0.025$
$n= 29$ half years
Using formula
$A=R\left[\frac{(1+i)^n-1}{i}\right]$
$100000= R\left[\frac{(1.025)^{20}-1}{0.025}\right]$
$R=\frac{100000×0.025}{(1.025)^{20}-1}$
Let $x= (1.025)^{20}$
Taking log on both sides, we get
$log\, x = 20\, log 1.025$
$log\, x = 20×0.0107$
$log\, x = 0.2140$
$x= antilog\, 0.2140$
$x= 1.637$
$R=\frac{2500}{1.637-1}=\frac{2500}{0.637}$
$R= ₹3924.64$