if $300 is deposited in an account and it increases to $450 in eight years compounded quarterly. find the rate of interest to the nearest tenth

Question

amistre64 · Answer

450 = 300(1+ r/4)^(8r)

amistre64 · Answer

http://www.wolframalpha.com/input/?i=450+%3D+300%281%2B+r%2F4%29^%288r%29

anonymous · Answer

and how do i solve that @amistre64

amistre64 · Answer

with cunning and style

amistre64 · Answer

46.28%

amistre64 · Answer

divide 300

take logs; and use rules of logs to manipulate it

amistre64 · Answer

or graph it and find the zero

anonymous · Answer

thank you

anonymous · Answer

can you show me step by step

amistre64 · Answer

i can try lol

anonymous · Answer

ok thanks lol

anonymous · Answer

@ amistr64 can i ask you a question when you done helping them

amistre64 · Answer

its easier on paper...

450/300= 3/2

3/2 = (1 + r/4)^(8r)

log(3/2) = log(1+ r/4)^(8r)

log(n) = 8r log(1+ r/4)

   log(n)
---------- = 8r
log(1 + r/4)

anonymous · Answer

so problems like this have to be solved with a calculator?

amistre64 · Answer

log(3) - log(2)
-------------- = 8r
log(4+r) - log(4)

        A
---------- = 8r
log(4+r) - B

log(4+r) - B = A/8r etc...

amistre64 · Answer

it canbe done by hand, but its alot of window dressing to get it to the right spot

anonymous · Answer

and the way you doing it here is by hand or calculator

anonymous · Answer

@amistre are you still there

amistre64 · Answer

by hand; which is why i left it alone really; :)

anonymous · Answer

oh ok