Final answer:
The balance after 7 years using simple interest at 5% is $16,200 and using compound interest at 4.5% is approximately $17,235.66. Compound interest yields a higher balance compared to simple interest for the same amount and period.
Step-by-step explanation:
The question involves calculating the balance of an investment after 7 years using two different interest earning methods: simple interest at a rate of 5% and compound interest at a rate of 4.5%.
Simple Interest Calculation:
Using the formula for simple interest
I = Prt,
where
I is the interest,
P is the principal amount ($12,000),
r is the rate of interest per year (0.05), and
t is the time in years (7),
we get:
I = $12,000 * 0.05 * 7 = $4,200
The total balance after 7 years with simple interest will be the principal plus the interest earned: $12,000 + $4,200 = $16,200.
Compound Interest Calculation:
Using the compound interest formula
A = P(1 + r/n)(nt),
where
A is the amount of money accumulated after n years, including interest,
P is the principal amount ($12,000),
r is the annual interest rate (0.045),
n is the number of times that interest is compounded per year, and
t is the time the money is invested for in years (7).
Assuming the interest is compounded once a year (n = 1), we get:
A = $12,000*(1 + 0.045/1)(1*7) = $12,000*(1.045)7 = $17,235.66 when rounded to two decimal places.
Comparing the two methods, the principle of compound interest results in a higher balance than simple interest over the same period, emphasizing its power to increase savings, especially over the long term.