$6,000 is invested in an account at interest rate r, compounded continuously. Find the time (in years) required for the amount to double when r= 9.5% and when r=2.5%.

When r= 9.5% , time = 7.3 years

When r= 2.5% , time = 27.7 years

Step-by-step explanation:

Exponential equation for compounded continuously:

, where P= Principal value invested , r= rate of interest, x= time

Given : P= $6,000

A = 2P= 2 ($6,000) = $12,000  (i)

When r= 9.5%= 0.095

 (ii)

From (i) and (ii)

For r= 2.5% = 0.025

correct answer:

i^31 = -i