$20000 @8%,bank returned $25,000,compounded continously,what is the time,using logathims,and how long to doubl

Answer 1

I understand this is the way schools do it in US
20000 exp(0.08n) = 25000
n = ln(25/20) /0.08 =2.789
so double n = ln(2)/0.08 = 8.664

In reality the "continuously compounded" rate should be
ln1.08 = 7.696%
If that sounds familiar to you, then adjust what I did before with the slightly lower rate.

Answer 2

To solve this question we use the equation A=Pe^(rt) where P is your principal and A is your total money earned...

So A = 25000
P = 20000
r = .08
Solve for t!

So we have 25000 = 20000e(.08t)...divide both sides by 20000....

then take the natural log of both sides:

ln(1.25) = lne(.08t) = ln(1.25) = .08*t

so t = ln(1.25)/.08

to solve for time to double, you just replace the 25000 with 40000 (20000*2) and solve for t again

Answer 3

It looks like you have two or three problems lumped together here. Check out the question.