How long does it take for a deposit of $900 to double at 9%?

Solution: We know that formula for continuously compound interest is:

Where A is the future amount $900 x 2 = $1800

P is the principal investment $900

e is the eular's constant

r is rate of interest 0.09

t is the time ( to be found)

Therefore we have:

Taking natural log on both sides

Therefore it will take 7.702 years to double the amount

step-by-step explanation:

20% of 120 is 24. if you subtract 24 from 120 you get 96