Answer:
Q1. Selena would have earned $25 in interest by the end of the year.
We calculate interest using the Simple Interest (SI) formula which is :
where
P = Principal or amount deposited
N = No. of years of deposit
R= Interest rate per annum
Substituting the values we have,
Q2. At the end of two years (eight quarters), the balance in the account will be $866.28 . That means Suki will have earned $66.28 in interest during that time.
We have
Amount deposited (P) = $800
Annual interest rate (i)= 4%
No. of compounding periods in a year (n)= 4
No. of years (t)= 2
We calculate amount at the end of two years with the following formula:
[tex]Compound interest = 866.2853645 - 800 = 66.2853645[/tex]
Q3. It will take 18 years for the money to double to $100.
The rule of 72 is used for determining the time period in which an investment doubles itself. We use this rule by dividing 72 by the interest rate.