Absolutely! Let’s solve each problem step by step using the
Simple Interest Formula:
>
I = P × r × t
Where:
-
I = Interest (what we’re solving for in most cases)
-
P = Principal (initial amount)
-
r = annual interest rate (as a decimal — divide % by 100)
-
t = time in
years (convert months to years by dividing by 12)
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##
✔ Part 1: Determine the simple interest for these loans.
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1) $450 at 7% for 2 years
I = 450 × 0.07 × 2 =
$63.00
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2) $5,200 at 4% for 3 years
I = 5200 × 0.04 × 3 =
$624.00
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3) $1,300 at 5% for 6 years
I = 1300 × 0.05 × 6 =
$390.00
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4) $5,400 at 3.5% for 6 months
→ 6 months = 6/12 = 0.5 years
I = 5400 × 0.035 × 0.5 =
$94.50
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5) $600 at 4% for 9 months
→ 9 months = 9/12 = 0.75 years
I = 600 × 0.04 × 0.75 =
$18.00
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6) $24,000 at 5.5% for 5 years
I = 24000 × 0.055 × 5 =
$6,600.00
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7) $15,600 at 3% for 2 years
I = 15600 × 0.03 × 2 =
$936.00
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8) $1,200 at 5.5% for 4 years
I = 1200 × 0.055 × 4 =
$264.00
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9) $1,600 at 4.5% for 9 months
→ 9/12 = 0.75 years
I = 1600 × 0.045 × 0.75 =
$54.00
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10) $12,000 at 2.2% for 5 years
I = 12000 × 0.022 × 5 =
$1,320.00
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##
✔ Part 2: Solve each simple interest word problem.
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11) A new car, valued at $28,000, depreciates at 9% per year. What is the value of the car one year after purchase?
⚠️ This is
depreciation, not interest, but we use the same math.
Depreciation amount = 28000 × 0.09 × 1 =
$2,520
Value after 1 year = 28000 - 2520 =
$25,480
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12) Sara puts $4,000 into an investment yielding 5% annual simple interest; she left the money in for five years. How much interest does Sara get at the end of those five years?
I = 4000 × 0.05 × 5 =
$1,000
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13) A bank is offering 3.5% simple interest on a savings account. If you deposit $7,500, how much interest will you earn in two years?
I = 7500 × 0.035 × 2 =
$525
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14) $400 interest is earned on a principal of $2,000 at a simple interest rate of 5% interest per year. For how many years was the principal invested?
We rearrange formula:
t = I / (P × r)
t = 400 / (2000 × 0.05) = 400 / 100 =
4 years
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15) In how many years will $1,200 yield an interest of $180 at 3% simple interest?
t = I / (P × r) = 180 / (1200 × 0.03) = 180 / 36 =
5 years
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16) Jim invested $4,000 in a bond at a yearly rate of 4.5%. He earned $540 in interest. How long was the money invested?
t = I / (P × r) = 540 / (4000 × 0.045) = 540 / 180 =
3 years
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## 📝 Final Answers Summary:
Part 1:
1) $63.00
2) $624.00
3) $390.00
4) $94.50
5) $18.00
6) $6,600.00
7) $936.00
8) $264.00
9) $54.00
10) $1,320.00
Part 2:
11) $25,480
12) $1,000
13) $525
14) 4 years
15) 5 years
16) 3 years
✔ All problems solved using the simple interest formula and careful unit conversion (months → years). Let me know if you’d like to see any step explained further!
Parent Tip: Review the logic above to help your child master the concept of simple interest math problems worksheet.
