3) alexandria was saving to take a trip after graduation. she put $3000 in the bank and it stayed there for…

3) alexandria was saving to take a trip after graduation. she put $3000 in the bank and it stayed there for 42 months, at 4.5% interest per year. how much interest did she earn?\n4) your grandmother gave you $1000 when you were ten to use for post - secondary education when you turned 18.\na) you invested it in an account for 8 years at 6.5% interest. how much interest have you earned?\nb) how much will you have in total for post - secondary education?\nc) a different account paid 7.5% interest instead. how much interest will you earn in the same amount of time?\nd) how much more money would you earn with the higher interest rate?\n5) $680 is invested at 3.5% simple interest. determine the total amount the investment will be worth after 4 years.

3) alexandria was saving to take a trip after graduation. she put $3000 in the bank and it stayed there for 42 months, at 4.5% interest per year. how much interest did she earn?\n4) your grandmother gave you $1000 when you were ten to use for post - secondary education when you turned 18.\na) you invested it in an account for 8 years at 6.5% interest. how much interest have you earned?\nb) how much will you have in total for post - secondary education?\nc) a different account paid 7.5% interest instead. how much interest will you earn in the same amount of time?\nd) how much more money would you earn with the higher interest rate?\n5) $680 is invested at 3.5% simple interest. determine the total amount the investment will be worth after 4 years.

Answer

Explanation:

Step1: Recall simple - interest formula

The simple - interest formula is $I = Prt$, where $I$ is the interest, $P$ is the principal amount, $r$ is the annual interest rate (in decimal form), and $t$ is the time in years.

Step2: Solve problem 3

First, convert the time to years. Since $42$ months, $t=\frac{42}{12}=3.5$ years, $P = 3000$, and $r = 0.045$. $I=Prt=3000\times0.045\times3.5 = 472.5$

Step3: Solve problem 4a

Here, $P = 1000$, $r=0.065$, and $t = 8$ years. $I=Prt=1000\times0.065\times8=520$

Step4: Solve problem 4b

The total amount $A$ is the sum of the principal and the interest. So $A=P + I$. Since $P = 1000$ and $I = 520$, $A=1000 + 520=1520$

Step5: Solve problem 4c

If $r = 0.075$, $P = 1000$, and $t = 8$ years. $I=Prt=1000\times0.075\times8 = 600$

Step6: Solve problem 4d

The difference in interest is $600−520 = 80$

Step7: Solve problem 5

First, find the interest. $P = 680$, $r=0.035$, and $t = 4$ years. $I=Prt=680\times0.035\times4=95.2$ The total amount $A=P + I=680+95.2 = 775.2$

Answer:

  1. $472.5$ 4a) $520$ 4b) $1520$ 4c) $600$ 4d) $80$
  2. $775.2$