The compound amount with continuous compounding is given by A=Pe^rt, where P is the principal, r is rate, and t the time in years. If he rate is 9%, find how long it takes for the money to double, that is for A=2P. (ln2=0.69315)

a. about 3.85 yrs
b. about 7.70 yr
c. about 15.40 yr
d. about 5.13 yr

Question

The compound amount with continuous compounding is given by A=Pe^rt, where P is the principal, r is rate, and t the time in years. If he rate is 9%, find how long it takes for the money to double, that is for A=2P. (ln2=0.69315)

a. about 3.85 yrs
b. about 7.70 yr
c. about 15.40 yr
d. about 5.13 yr

ganeshie8 · Answer

plugin 
A = 2P
r = 9% = .09

ganeshie8 · Answer

$\large   A = Pe^{rt}$

$\large  2P = Pe^{0.09t}$

$\large  2 = e^{0.09t}$

ganeshie8 · Answer

take natural log both sides and solve $t$

anonymous · Answer

Great! Thank you so much for the help =)

ganeshie8 · Answer

np :)