The interest rate r required to increase your investment p to the amount a in t years is found by
r=(a/p)1/t−1
. Find the interest rate r for p = 8100, a = 10,000, and t = 2. Round to the nearest hundredth.

Question

The interest rate r required to increase your investment p to the amount a in t years is found by 
r=(a/p)1/t−1
. Find the interest rate r for p = 8100, a = 10,000, and t = 2. Round to the nearest hundredth.

anonymous · Answer

For medal and fan (:

anonymous · Answer

goo tkhunny lol

tkhunny · Answer

Let's see if we can find that formula...

$a = p\cdot (1+r)^t$

$\dfrac{a}{p} = (1+r)^t$

$\left(\dfrac{a}{p}\right)^{1/t} = 1+r$

$r = \left(\dfrac{a}{p}\right)^{1/t} - 1$

Ah!  That makes SO MUCH more sense.  Please find a way to write clearly.  Learning just a little LaTeX would go a very long way.

anonymous · Answer

not exactly. :/ thanks for the help

tkhunny · Answer

Can we now substitute?

p = 8100
a = 10,000
t = 2