How long will it take for $5600 to triple at an interest rate of 2.25% if the interest is compounded continuously?

Question

I must round to the nearest year. I gave this problem a try and received the answer of t = 0.488. But I’m not quite sure if that’s correct.

Answer 1

A=Pe^(rt)

P=5600

A = 3P = 16800

r=0.0225

t =?

divide both sides by P

3=e^(rt)

natural log both sides

ln(3) = rt

divide both sides by r

ln(3)/r =t

ln(3)/0.0225 = 48.8 round is 49.

so your numbers are right, but the order of magnitude is off.

you probably used r=2.25 instead of r=2.25%=0.0225