# At what rate percent per annum will a sum of money doubles in 3 years at Si *?

 Text SolutionSolution : Given:
Time Period (t)=3 years
Let the Principal (P) be Rs.100
Then the Amount (A) will be Rs.200 as given in the question that the money will be doubled.
And let the rate be R.
As we know that:
A=P(1+R/100)^t
therefore 200=100(1+R/100)^3
200/100=((100+R)/100)^3
2=((100+R)/100)^3
root(3)(2)=(100+R)/100
1.2599=(100+R)/100
1.2599times100=100+R
125.99=R+100
R=125.99-100
R=25.99% per annum.
Hence, the rate at which sum of money is doubled in 3 years is 25.99% per annum. India's Super Teachers for all govt. exams Under One Roof Enroll For Free Now Formula for Simple Interest - $$SI = \frac{{P \times R \times T}}{{100}}$$ Where, P = Principal R = Rate of interest T = Time period Let the required rate of interest be X. According to the question, SI must be equal to 2 × P in order to make the final sum two times the original principal amount after 5 year. $$\therefore {\rm{P}} = {\rm{}}\frac{{{\rm{P}} \times {\rm{X}} \times 5}}{{100}}$$ ⇒ X = 20% ∴ Required rate of interest is of 20%. Ace your Interest preparations for Simple Interest with us and master Quantitative Aptitude for your exams. Learn today! India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Get Started for Free Download App Trusted by 3.4 Crore+ Students Right on! Give the BNAT exam to get a 100% scholarship for BYJUS coursesNo worries! We‘ve got your back. Try BYJU‘S free classes today!No worries! We‘ve got your back. Try BYJU‘S free classes today!No worries! We‘ve got your back. Try BYJU‘S free classes today!Open in App Suggest Corrections12