In how much time Rs. 64000 will amount Rs. 68921 at the rate of 10% compound interest per annum if interest is compounded quarterly?

Explanation

Here `p=Rs. 64000, A=Rs. 68921,r=10`
Let the required time `=n` years
As per question `A=p(1+(r/4)/100)^(4n)`
`impliesRs. 64000(1+(10/4)/100)^(4n)=Rs. 68921`
or `(1+1/40)^(4n)=68921/64000` or `(41/40)^(4n)=(41/40)^(3)`
`implies4n=3impliesn=3/4=3/4xx12` months `=9` months
Hence the required time `=9` months.