Piecewise function problem for calculating income tax based on different income brackets.
A math problem on applications of piecewise functions showing income tax rates, with a piecewise function and graph for income tax calculation.
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Step-by-step solution for: Applications of Piecewise Functions
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Show Answer Key & Explanations
Step-by-step solution for: Applications of Piecewise Functions
It looks like you've uploaded a problem about applications of piecewise functions related to income tax, and there's also a "Your Scenario" section at the bottom with different tax brackets. Let's solve both parts carefully.
---
> In a certain country, income tax is assessed as follows:
> - No tax on income up to $15,000
> - Income over $15,000 and up to $30,000 is taxed at 12%
> - Income over $30,000 is taxed at 18%
We are asked to:
a) Write the piecewise function and sketch its graph
b) Determine how much tax is paid on an income of $17,000
---
## ✔ Part (a): Write the Piecewise Function
Let’s define $ f(x) $ as the tax amount for an income of $ x $ dollars.
The tax is applied only to the portion of income in each bracket, not the entire income.
So we need to define $ f(x) $ piecewise based on income levels.
- For $ x \leq 15,000 $: No tax → $ f(x) = 0 $
- For $ 15,000 < x \leq 30,000 $: Tax only the amount above $15,000 at 12%
- So: $ f(x) = 0.12(x - 15,000) $
- For $ x > 30,000 $:
- First $15,000 → no tax
- Next $15,000 ($15,001 to $30,000) → taxed at 12%
- Amount over $30,000 → taxed at 18%
- So: $ f(x) = 0.12(30,000 - 15,000) + 0.18(x - 30,000) $
- Simplify: $ f(x) = 0.12(15,000) + 0.18(x - 30,000) = 1,800 + 0.18(x - 30,000) $
$$
f(x) =
\begin{cases}
0, & x \leq 15,000 \\
0.12(x - 15,000), & 15,000 < x \leq 30,000 \\
1,800 + 0.18(x - 30,000), & x > 30,000
\end{cases}
$$
---
- From $ x = 0 $ to $ x = 15,000 $: Flat line at $ f(x) = 0 $
- From $ x = 15,000 $ to $ x = 30,000 $: Straight line starting at (15,000, 0) with slope 0.12
- At $ x = 30,000 $: $ f(30,000) = 0.12(15,000) = 1,800 $
- For $ x > 30,000 $: Line starting at $ (30,000, 1,800) $ with steeper slope (0.18)
So the graph is:
- Horizontal from (0,0) to (15,000, 0)
- Then upward-sloping with slope 0.12 until (30,000, 1,800)
- Then upward-sloping with slope 0.18 beyond that
---
## ✔ Part (b): Tax on $17,000
Since $ 15,000 < 17,000 \leq 30,000 $, use the second case:
$$
f(17,000) = 0.12(17,000 - 15,000) = 0.12 \times 2,000 = 240
$$
✔ Answer: $240 tax is due on $17,000 income.
---
## ❗ But Wait — There's a "Your Scenario" at the Bottom!
You wrote:
> Your Scenario: There is no tax on income up to $12,000. Income over $12,000 and up to $25,000 is taxed at 10%. Income over $25,000 is taxed at 16%.
This appears to be a different problem — possibly your own version or a typo.
Let’s solve that one too, just in case it’s what you're supposed to answer.
---
## 🔸 Your Scenario (Alternative Problem)
Tax rules:
- $ x \leq 12,000 $: $ f(x) = 0 $
- $ 12,000 < x \leq 25,000 $: taxed at 10% on amount over $12,000
- $ x > 25,000 $: taxed at 16% on amount over $25,000, plus previous taxes
$$
f(x) =
\begin{cases}
0, & x \leq 12,000 \\
0.10(x - 12,000), & 12,000 < x \leq 25,000 \\
0.10(25,000 - 12,000) + 0.16(x - 25,000), & x > 25,000
\end{cases}
$$
Simplify third case:
- $ 0.10 \times 13,000 = 1,300 $
- So: $ f(x) = 1,300 + 0.16(x - 25,000) $
- Flat at 0 up to $12,000
- Slope 0.10 from $12,000 to $25,000 → ends at $ f(25,000) = 1,300 $
- Then slope 0.16 beyond $25,000
---
## ✔ Now, if you want to find tax on $17,000 under your scenario:
$ 12,000 < 17,000 \leq 25,000 $ → use second case:
$$
f(17,000) = 0.10(17,000 - 12,000) = 0.10 \times 5,000 = 500
$$
✔ So under your scenario, tax on $17,000 is $500
---
## 🟩 Final Answers
- Piecewise function:
$$
f(x) =
\begin{cases}
0, & x \leq 15,000 \\
0.12(x - 15,000), & 15,000 < x \leq 30,000 \\
1,800 + 0.18(x - 30,000), & x > 30,000
\end{cases}
$$
- Tax on $17,000: $ \boxed{240} $
- Piecewise function:
$$
f(x) =
\begin{cases}
0, & x \leq 12,000 \\
0.10(x - 12,000), & 12,000 < x \leq 25,000 \\
1,300 + 0.16(x - 25,000), & x > 25,000
\end{cases}
$$
- Tax on $17,000: $ \boxed{500} $
---
Let me know which one you were supposed to solve — but I’ve covered both!
---
🔹 Problem Statement (Original):
> In a certain country, income tax is assessed as follows:
> - No tax on income up to $15,000
> - Income over $15,000 and up to $30,000 is taxed at 12%
> - Income over $30,000 is taxed at 18%
We are asked to:
a) Write the piecewise function and sketch its graph
b) Determine how much tax is paid on an income of $17,000
---
## ✔ Part (a): Write the Piecewise Function
Let’s define $ f(x) $ as the tax amount for an income of $ x $ dollars.
The tax is applied only to the portion of income in each bracket, not the entire income.
So we need to define $ f(x) $ piecewise based on income levels.
Step-by-step breakdown:
- For $ x \leq 15,000 $: No tax → $ f(x) = 0 $
- For $ 15,000 < x \leq 30,000 $: Tax only the amount above $15,000 at 12%
- So: $ f(x) = 0.12(x - 15,000) $
- For $ x > 30,000 $:
- First $15,000 → no tax
- Next $15,000 ($15,001 to $30,000) → taxed at 12%
- Amount over $30,000 → taxed at 18%
- So: $ f(x) = 0.12(30,000 - 15,000) + 0.18(x - 30,000) $
- Simplify: $ f(x) = 0.12(15,000) + 0.18(x - 30,000) = 1,800 + 0.18(x - 30,000) $
✔ Final Piecewise Function:
$$
f(x) =
\begin{cases}
0, & x \leq 15,000 \\
0.12(x - 15,000), & 15,000 < x \leq 30,000 \\
1,800 + 0.18(x - 30,000), & x > 30,000
\end{cases}
$$
---
📈 Sketching the Graph:
- From $ x = 0 $ to $ x = 15,000 $: Flat line at $ f(x) = 0 $
- From $ x = 15,000 $ to $ x = 30,000 $: Straight line starting at (15,000, 0) with slope 0.12
- At $ x = 30,000 $: $ f(30,000) = 0.12(15,000) = 1,800 $
- For $ x > 30,000 $: Line starting at $ (30,000, 1,800) $ with steeper slope (0.18)
So the graph is:
- Horizontal from (0,0) to (15,000, 0)
- Then upward-sloping with slope 0.12 until (30,000, 1,800)
- Then upward-sloping with slope 0.18 beyond that
---
## ✔ Part (b): Tax on $17,000
Since $ 15,000 < 17,000 \leq 30,000 $, use the second case:
$$
f(17,000) = 0.12(17,000 - 15,000) = 0.12 \times 2,000 = 240
$$
✔ Answer: $240 tax is due on $17,000 income.
---
## ❗ But Wait — There's a "Your Scenario" at the Bottom!
You wrote:
> Your Scenario: There is no tax on income up to $12,000. Income over $12,000 and up to $25,000 is taxed at 10%. Income over $25,000 is taxed at 16%.
This appears to be a different problem — possibly your own version or a typo.
Let’s solve that one too, just in case it’s what you're supposed to answer.
---
## 🔸 Your Scenario (Alternative Problem)
Tax rules:
- $ x \leq 12,000 $: $ f(x) = 0 $
- $ 12,000 < x \leq 25,000 $: taxed at 10% on amount over $12,000
- $ x > 25,000 $: taxed at 16% on amount over $25,000, plus previous taxes
✔ Piecewise Function:
$$
f(x) =
\begin{cases}
0, & x \leq 12,000 \\
0.10(x - 12,000), & 12,000 < x \leq 25,000 \\
0.10(25,000 - 12,000) + 0.16(x - 25,000), & x > 25,000
\end{cases}
$$
Simplify third case:
- $ 0.10 \times 13,000 = 1,300 $
- So: $ f(x) = 1,300 + 0.16(x - 25,000) $
Graph:
- Flat at 0 up to $12,000
- Slope 0.10 from $12,000 to $25,000 → ends at $ f(25,000) = 1,300 $
- Then slope 0.16 beyond $25,000
---
## ✔ Now, if you want to find tax on $17,000 under your scenario:
$ 12,000 < 17,000 \leq 25,000 $ → use second case:
$$
f(17,000) = 0.10(17,000 - 12,000) = 0.10 \times 5,000 = 500
$$
✔ So under your scenario, tax on $17,000 is $500
---
## 🟩 Final Answers
✔️ Original Problem (as stated):
- Piecewise function:
$$
f(x) =
\begin{cases}
0, & x \leq 15,000 \\
0.12(x - 15,000), & 15,000 < x \leq 30,000 \\
1,800 + 0.18(x - 30,000), & x > 30,000
\end{cases}
$$
- Tax on $17,000: $ \boxed{240} $
✔️ Your Scenario:
- Piecewise function:
$$
f(x) =
\begin{cases}
0, & x \leq 12,000 \\
0.10(x - 12,000), & 12,000 < x \leq 25,000 \\
1,300 + 0.16(x - 25,000), & x > 25,000
\end{cases}
$$
- Tax on $17,000: $ \boxed{500} $
---
Let me know which one you were supposed to solve — but I’ve covered both!
Parent Tip: Review the logic above to help your child master the concept of piecewise functions word problems worksheet.