Better Students Ask More Questions.
According to the following, how many years until the value of the CD is double the...
According to the following, how many years until the value of the CD is double the amount originally invested ( round answer to the nearest year?
bob invested $1000 in a bank CD. the CD earns 3% interest compunded annually. using the formula, A=P(1+r)t, where A = value of CD, P=principle (original) amount invested, r=interest rate (in decimal form), and t=time in years, determine the followingal form), and t=time in years, determine the follow
2 Answers | add yours
Posted by sammysoso on February 10, 2011 at 6:47 AM (Answer #1)
High School Teacher
A = Value of CD
P = original amount= 1000
r = the rate = 3% = 0.03
We need to find t such that A is doubled
==> A = 2*1000 = 2000
Now we will substitute.
==> 2000 = 1000( 1+0.03)^t
==> 2000= 1000(1.03)^t
Divide by 1000
==> 2= (1.03)^t
Apply logarithm to both sides.
==> log 2 = log (1.03)^t
==> log 2 = t*log (1.03)
==> t= log 2 / log 1.03
==> t= 23.4 years
Then the time needed if 23 years.
Posted by hala718 on February 10, 2011 at 8:34 AM (Answer #2)
Join to answer this question
Join a community of thousands of dedicated teachers and students.