math
posted by Dexter on .
Barbara knows that she will need to buy a new car in 4 years. The car will cost $15,000 by then. How much should she invest now at 10%, compounded quarterly, so that she will have enough to buy a new car? Round to the nearest cent.

solve for x
x(1.025)^16 = 15000 
im not sure how to complete the problem becuase my answer was 9312.82, not sure if this is correct

I have no idea how you got that.
I am using the standard formula
Amount = principal(1 + i)^n
where i is the periodic interest rate, and n is the number of interest periods
the rate is 10% p.a., compounded quarterly , so i = .10/4 = .025
and the time is 4 years or 16 quarter years, hence n = 16
so
x(1.025)^16 = 15000
x(1.484505621) = 15000
http://www.google.ca/search?hl=en&source=hp&q=1.025%5E16&meta=&aq=f&aqi=&aql=&oq=&gs_rfai=
x = 15000/1.484505621
= 10104.37
http://www.google.ca/search?hl=en&source=hp&q=1.025%5E16&meta=&aq=f&aqi=&aql=&oq=&gs_rfai= 
ok i get it , thanks