Question

How long would it take $2,500 to grow to $9,700 if the annual rate is 4.1% and interest in compounded monthly?

If $8,000 is placed in an account with an annual interest rate of 4%, how long will it take the amount to quadruple if the interest is compounded annually? Round your answer to two decimal places.

The bacteria in a certain culture double every 6.5 hours. The culture has 7,500 bacteria at the start.
How many bacteria will the culture contain after 4 hours?

Answer 1

How long would it take $2,500 to grow to $9,700 if the annual rate is 4.1% and interest in compounded monthly?


A = P(1+r/n)^(n*t)

9700 = 2500(1+0.041/12)^(12*t)

9700 = 2500(1+0.003416667)^(12*t)

9700 = 2500(1.003416667)^(12*t)

9700/2500 = (1.003416667)^(12*t)

3.88 = (1.003416667)^(12*t)

(1.003416667)^(12*t) = 3.88

log( (1.003416667)^(12*t) ) = log( 3.88 )

12*t*log( 1.003416667 ) = log( 3.88 )

I'll let you finish

Answer 2

Got it thank you. I got the second one as well. I just need help with the last one.

Answer 3

A = P*2^(6.5/t)

A = 7500*2^(6.5/t)

A = 7500*2^(6.5/4)

A = 7500*2^(1.625)

..
..

A = ??

Answer 4

23,133

Answer 5

Thank you! :)

Answer 6

nailed it

Answer 7

Thanks so much for your help!

Answer 8

yw