A woman invests $5800 in an account that pays 6% interest per year, compounded continuously.

a) What is the amount after 2 years? (Round your answer to the nearest cent.)
b) How long will it take for the amount to be $8000? (Round your answer to two decimal places.)

Respuesta :

Answer:

Part a) [tex]\$6,539.48[/tex]  

Part b) [tex]5.36\ years[/tex]  

Step-by-step explanation:

we know that

The formula to calculate continuously compounded interest is equal to

[tex]A=P(e)^{rt}[/tex]  

where  

A is the Final Investment Value  

P is the Principal amount of money to be invested  

r is the rate of interest in decimal  

t is Number of Time Periods  

e is the mathematical constant number

Part a) What is the amount after 2 years?

we have  

[tex]t=2\ years\\ P=\$5,800\\ r=0.06[/tex]  

substitute in the formula above  

[tex]A=\$5,800(e)^{0.06*2}=\$6,539.48[/tex]  

Part b) How long will it take for the amount to be $8000?

we have  

[tex]t=?\ years\\ P=\$5,800\\ r=0.06\\A=\$8,000[/tex]  

substitute in the formula above  and solve for t

[tex]\$8,000=\$5,800(e)^{0.06t}[/tex]  

[tex](8,000/5,800)=(e)^{0.06t}[/tex]  

Applying ln both sides

Remember that

ln(e)=1

[tex]ln(8,000/5,800)=0.06t[/tex]  

[tex]t=ln(8,000/5,800)/0.06=5.36\ years[/tex]