Question

Jari invests in a CD with an annual interest rate of 6.90% compounded quarterly. How many years will it take for Jari's investment to double. Round your answer 4 decimal places and include a label

Answer 1

Answer:   10.1246 years (approx)

Step-by-step explanation:

Here, She invests in a CD with an annual interest rate of 6.90% compounded quarterly.

Let the initial amount or principal = P

And, Let after t years it is doubled.

Therefore, $2P= P(1+\frac{6.9}{400} )^{4t}$

⇒ $2 = (1+\frac{6.9}{400} )^{4t}$

⇒$log 2 = t log(1+\frac{6.9}{400} )^4$ ( By taking log both sides)

⇒$log 2 = t log(1.01725 )^4$

⇒t= log 2/log 1.07080599536= 10.1245504311≈10.1246 years