Worksheet for calculating simple interest to find ending balance.

To solve these problems, we use the simple interest formula:

$$
I = P \times r \times t
$$

Where:
- $ I $ = Interest earned
- $ P $ = Principal (initial amount)
- $ r $ = Annual interest rate (as a decimal)
- $ t $ = Time in years

Then, the ending balance is:

$$
\text{Ending Balance} = P + I
$$

We'll go through each problem step by step.

---

1) $450 at 7% for 2 years

- $ P = 450 $
- $ r = 7\% = 0.07 $
- $ t = 2 $

$$
I = 450 \times 0.07 \times 2 = 63
$$
$$
\text{Ending Balance} = 450 + 63 = \boxed{\$513}
$$

---

2) $12,000 at 2.2% for 5 years

- $ P = 12,000 $
- $ r = 2.2\% = 0.022 $
- $ t = 5 $

$$
I = 12,000 \times 0.022 \times 5 = 1,320
$$
$$
\text{Ending Balance} = 12,000 + 1,320 = \boxed{\$13,320}
$$

---

3) $1,300 at 5% for 6 years

- $ P = 1,300 $
- $ r = 0.05 $
- $ t = 6 $

$$
I = 1,300 \times 0.05 \times 6 = 390
$$
$$
\text{Ending Balance} = 1,300 + 390 = \boxed{\$1,690}
$$

---

4) $1,300 at 5% for 6 years

This is identical to #3.

$$
\text{Ending Balance} = \boxed{\$1,690}
$$

---

5) $5,400 at 3.5% for 6 months

- $ P = 5,400 $
- $ r = 3.5\% = 0.035 $
- $ t = 6 \text{ months} = 0.5 \text{ years} $

$$
I = 5,400 \times 0.035 \times 0.5 = 94.50
$$
$$
\text{Ending Balance} = 5,400 + 94.50 = \boxed{\$5,494.50}
$$

---

6) $24,000 at 8.5% for 9 years

- $ P = 24,000 $
- $ r = 0.085 $
- $ t = 9 $

$$
I = 24,000 \times 0.085 \times 9 = 18,360
$$
$$
\text{Ending Balance} = 24,000 + 18,360 = \boxed{\$42,360}
$$

---

7) $24,000 at 5.5% for 5 years

- $ P = 24,000 $
- $ r = 0.055 $
- $ t = 5 $

$$
I = 24,000 \times 0.055 \times 5 = 6,600
$$
$$
\text{Ending Balance} = 24,000 + 6,600 = \boxed{\$30,600}
$$

---

8) $600 at 4% for 9 months

- $ P = 600 $
- $ r = 0.04 $
- $ t = 9 \text{ months} = 0.75 \text{ years} $

$$
I = 600 \times 0.04 \times 0.75 = 18
$$
$$
\text{Ending Balance} = 600 + 18 = \boxed{\$618}
$$

---

9) $5,400 at 7.5% for 6 months

- $ P = 5,400 $
- $ r = 0.075 $
- $ t = 0.5 $

$$
I = 5,400 \times 0.075 \times 0.5 = 202.50
$$
$$
\text{Ending Balance} = 5,400 + 202.50 = \boxed{\$5,602.50}
$$

---

10) $1,400 at 4.5% for 9 months

- $ P = 1,400 $
- $ r = 0.045 $
- $ t = 0.75 $

$$
I = 1,400 \times 0.045 \times 0.75 = 47.25
$$
$$
\text{Ending Balance} = 1,400 + 47.25 = \boxed{\$1,447.25}
$$

---

✔ Final Answers:

1) \$513
2) \$13,320
3) \$1,690
4) \$1,690
5) \$5,494.50
6) \$42,360
7) \$30,600
8) \$618
9) \$5,602.50
10) \$1,447.25

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