Question 1102759
Compound interest formula is P=Po(1+r/n)^nt
P=1000(1+(0.00025)/4)^48=$1003.
Perhaps it is 2.5% interest or 0.025
Then it is 1000(1+.025/4)^48=$1348.60.
Using the 2.5% interest
10000=1000(1+.025/4)^4t, where t is number of years
10=1.00625^4t
ln both sides
2.303=4t*ln(1.00625)
369.56 compoundings=4t
t=92.39 years round to 93 years
rule of 72 says 72/2.5=doubling time in years which is about 28 years.
doubles a second time at 56 years (to $4000) and again at 84 years (to $8000), so that 93 years is a reasonable answer.
(for the 0.00025 interest, it would be 9210 years.)