Question

PLZZZ HELP

Answer 1

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 :

$SI = P*N*R$

where

P = Principal or amount deposited

N = No. of years of deposit

R= Interest rate per annum

Substituting the values we have,

$SI = 500 * 1 * 0.05 = 25$

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:

$\mathbf{A = P * \left (1+\frac{i}{n}\right )^{nt}}$

$\mathbf{A = 800 * \left (1+\frac{0.04}{4}\right )^{4*2}}$

$\mathbf{A = 800 * \left (1.01)^{8}} = 866.2854$

$Compound interest = Total amount received - Amount deposited$

[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.

So, $\frac{72}{4} = 18 years$