A person invests $2,740 in an account that earns 4.3% annual interest. Find when the value of the investment reaches $7,000. If necessary, round to the nearest tenth. the investment will reach $7,000 in approximatelyyears.

So, to set up your equation is the hardest part. If you remember the basic format, you're set.

I (t) = P * (1+r%) ^t

t = time and this will be our variable

Initial amount P = $2740

Rate = 4.3% which converts numerically into. 043

I (t) = 7000

Before we get to find out how to find how many years it takes to get to $7000, set up the basic equation by plugging in what we know.

I (t) = $2740 (1+4.3%) ^t

I (t) = 2740 (1.043) ^t

Now plug in for $7000 for I (t)

7000=2740 (1.043) ^t Divide both sides by 2740

7000/2740 = 2740/2740 (1.043) ^t

2.55474453 = (1.043) ^t

Now you can solve for t in two ways. You can either use the natural log or graph it on your graphing calculate and see when the two equations meet.

In your calculator you can set up:

ln (2.55474453) / ln (1.043) = t which is the method I prefer since it's much simpler

t=22.278528

but you can also graph it in your ti-84

with

y1=2.55474453

y2 = (1.043) ^x

and find where they intersect on the graph.

either way it'll be the same answer