Tina wants to save money for school. Tina invests $1000 in an account that pays an interest rate of 8%. How many years will it take for the account to reach $1300? Round your answer to the nearest hundredth.

Question

amistre64 · Answer

do we assume a compounded rate of once a year?

anonymous · Answer

I guess.

anonymous · Answer

A=P(r+1)^t

amistre64 · Answer

if so, then:

1300 = 1000 (1+.08)^t  ; divide out the 1000

1300/1000 = (1.08)^t  ; now ln it all

ln(13/10) = ln[(1.08)^t] ; apply log rules

ln(13/10) = t * ln(1.08)  ; and divide out the ln(1.08)

ln(13/10)/ln(1.08) = t

anonymous · Answer

So it's 1.08..?

amistre64 · Answer

dunno; the calculator has to figure that out ....

amistre64 · Answer

google has a nice calculator feature; just type it in the search box and it should just pop out an answer

anonymous · Answer

Type in ln(13/10)/ln(1.08) = t ?

amistre64 · Answer

http://www.google.com/search?sourceid=chrome&ie=UTF-8&q=ln(13%2F10)%2Fln(1.08)

amistre64 · Answer

not the "=t" part :)

anonymous · Answer

Ok thanks.

amistre64 · Answer

to dbl chk the results; insert the value you get for "t" into the original equation