7100 dollars is placed in an account with an annual interest rate of 5%. To the nearest tenth of a year, how long will it take for the account value to reach 26400 dollars ?

Respuesta :

Answer:

After [tex]26.91\ years[/tex] the principle amount value will reach to [tex]26400\ dollars[/tex].

Step-by-step explanation:

Given that,

                 Principle Amount [tex](P)= 7100\ dollars[/tex]

                 Rate of Interest [tex](R)=[/tex] [tex]5[/tex]%

                 Total Amount [tex](A)= 26400\ dollars[/tex]

If Principle Amount [tex](P)[/tex] [tex]=P\ dollars[/tex], Time [tex]=t\ years[/tex], Rate of Interest [tex]=R[/tex]% [tex]pa[/tex]

when interest is compounded annually:

Total Amount after [tex]t\ years[/tex] [tex]= P(1+\frac{R}{100}) ^{t}[/tex]

Now,

         [tex]A= P(1+\frac{R}{100}) ^{t}[/tex]

     ⇒ [tex]26400=7100(1+\frac{5}{100}) ^{t}[/tex]

     ⇒ [tex]3.7183=(1+0.05)^{t}[/tex]

     ⇒ [tex]3.7183=(1.05)^{t}[/tex]

taking log both sides, we get

         [tex]ln(3.7183)=ln {(1.05)^{t}}[/tex]

     ⇒ [tex]1.31327=t\times ln(1.05)[/tex]

     ⇒ [tex]1.31327=t\times 0.04879[/tex]

    ⇒ [tex]t=26.91[/tex]

Therefore,

After [tex]26.91\ years[/tex] the principle amount value will reach to [tex]26400\ dollars[/tex].

Answer: x=26.9

Step-by-step explanation: