130k views
2 votes
If you invest P dollars and you want the investment to grow to A dollars in t years, the interest rate that must be earned if interest is compounded annually is given by the formula r = t √ A P − 1 If you invest $ 1500 and want to have $ 6000 in 8 years, what interest rate must be earned? Round to at least 1 decimal place. You need an interest rate of at least 1.19 Incorrect percent.

User Turushan
by
6.1k points

2 Answers

6 votes

Answer: 6%

Step-by-step explanation:

Just too, it

User The WebMacheter
by
4.9k points
1 vote

Answer: 18.92%

Step-by-step explanation:

The formula to find the compound amount :-


A=P(1+r)^t, where P is the Principal amount, r is the rate of interest and t is the time period.

Given : P= $1500

A = $6000

Time = 8 years

Then
6000=1500(1+r)^8

i.e.
(1+r)^8=(6000)/(1500)=4

i

Taking natural log on both sides , we get


\Rightarrow\ 8\ln(1+r)=\ln(4)\\\\\Rightarrow\ \log(1+r)=(\log4)/(8)=(1.38629436112)/(8)=0.17328679514\\\\\Rightrarrow\ 1+r=e^(0.17328679514)\\\\\Rightarrow\ 1+r=1.189207115\\\\\Rightarrow\ r=1.189207115-1=0.189207115\\\\\Rightarrow\ r\approx0.1892\approx18.92\%

User Abdulkabir Ojulari
by
4.9k points