Question

Can someone help me super fast with question 7 and 8!! I need the answer and explanation please!!!

I think you are supposed to use the formula p(1+rt) but I’m not sure!!


Question 7:

Juan wants to invest $6800 in a savings account that pays 4.7% simple interest. How long will it take for this investment to double in value? Round your answer to the nearest tenth.
Find the years.



Question 8:

How much would you need to deposit in an account now in order to have $4000 in the account in 10 years? Assume the account earns 5% simple interest. Round your answer to the nearest cent.



Thank you!!

Answer 1

Question 7:

`6800( {1.047}^(t) ) = 13600`

`{1.047}^(t) = 2`

`t = ( ln(2) )/( ln(1.047) ) = 15.1 \: years`

Question 8:

`p( {1.05}^(10) ) = 4000`

`p = \frac{4000}{ {1.05}^(10) } = 2455.65`

The deposit is $2,455.65.