Math Snap
PROBLEM
Calculate and compare interest for Laura's compound and Eric's simple interest on $70,000 at 3\% for 3 years.
STEP 1
Assumptions1. Laura's account compounds interest annually.
. Eric's account earns simple interest.
3. Both Laura and Eric deposit $70,000.
4. The annual interest rate for both accounts is3%.
5. There are no withdrawals and no additional deposits.
6. We need to calculate the interest earned for each of the first three years.
STEP 2
First, we need to understand the formulas for calculating simple and compound interest.
For simple interestFor compound interestThen, to find the interest, subtract the principal from the amount.
STEP 3
Let's calculate the simple interest for Eric for each of the first three years.
For year1Interest = \($\)70,000 \times3\% \times1For year2Interest = \($\)70,000 \times3\% \times1For year3Interest = \($\)70,000 \times3\% \times1
STEP 4
Convert the percentage to a decimal value.
Then, calculate the interest for each year.
STEP 5
Calculate the simple interest for Eric for each of the first three years.
For year1Interest = \($\)70,000 \times0.03 \times1 = \($\)2,100For year2Interest = \($\)70,000 \times0.03 \times1 = \($\)2,100For year3Interest = \($\)70,000 \times0.03 \times1 = \($\)2,100
STEP 6
Now, let's calculate the compound interest for Laura for each of the first three years.
For year1Amount = \($\)70,000 \times (1 +0.03)^1For year2Amount = \($\)70,000 \times (1 +0.03)^2For year3Amount = \($\)70,000 \times (1 +0.03)^3
STEP 7
Calculate the compound interest for Laura for each of the first three years.
For year1Amount = \($\)70,000 \times (1 +0.03)^1 = \($\)72,100Interest = \($\)72,100 - \($\)70,000 = \($\)2,100For year2Amount = \($\)70,000 \times (1 +0.03)^2 = \($\)74,263Interest = \($\)74,263 - \($\)70,000 = \($\)4,263For year3Amount = \($\)70,000 \times (1 +0.03)^3 = \($\)76,490.89Interest = \($\)76,490.89 - \($\)70,000 = \($\)6,490.89
SOLUTION
Now, let's compare the interest earned by Laura and Eric for each of the first three years.
For year1, both Laura and Eric earn $2,100.
For year2, Laura earns $4,263 and Eric earns $2,100. Laura earns more.
For year3, Laura earns $6,490.89 and Eric earns $2,100. Laura earns more.
So, Laura earns more interest than Eric for each year after the first year.