Question

at what rate of interest per annum , the amount rs 10,000/- will be doubled in 5 years,interest being compounded quarterly?

Answer 1

PRinciplap = 10,000
We want to know wate % = let it be r%
  We also want double of it in 5 year = doubles amout we want = 10,000+10,000 = 20,000
    Now 
      $Amount = Pricipal( 1+\frac{r}{100}) x^{5}$
         20,000=10,000( 100+r/100)5
         And solve it