# Nakafa Framework: LLM

URL: https://nakafa.com/en/exercises/high-school/snbt/quantitative-knowledge/try-out/set-10/6

Exercises: Try Out - Set 10: Real exam simulation to sharpen your skills and build confidence. - Book Discount

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## Exercise 6

### Question

export const metadata = {
  title: "Book Discount",
  authors: [{ name: "Nabil Akbarazzima Fatih" }],
  date: "12/27/2025",
};

The price of a math book at ABC store is <InlineMath math="85,000" /> rupiah and a biology book is priced at <InlineMath math="40,000" /> rupiah. Because the store is having an anniversary, all books are given an <InlineMath math="x\%" /> discount. If on that day the price of a math book is <InlineMath math="28,900" /> rupiah. What is the price of the biology book?


### Choices

- [ ] $$11,760$$
- [ ] $$12,000$$
- [x] $$13,600$$
- [ ] $$14,000$$
- [ ] $$15,600$$

### Answer & Explanation

export const metadata = {
  title: "Book Discount Explanation",
  authors: [{ name: "Nabil Akbarazzima Fatih" }],
  date: "12/27/2025",
};

Given:
-   Original price of math book = <InlineMath math="85,000" />
-   Price of math book after discount = <InlineMath math="28,900" />
-   Original price of biology book = <InlineMath math="40,000" />

We need to find the percentage of the price to be paid (price after discount) relative to the original price. Let's find this ratio.

Based on the math book price:

<MathContainer>
  <BlockMath math="\frac{\text{Final Price}}{\text{Original Price}} = \frac{28,900}{85,000}" />
</MathContainer>

Simplify the fraction:

<MathContainer>
  <BlockMath math="\frac{28,900}{85,000} = \frac{289}{850} = \frac{17 \times 17}{17 \times 50} = \frac{17}{50}" />
</MathContainer>

Or as a percentage:

<MathContainer>
  <BlockMath math="\frac{17}{50} \times 100\% = 34\%" />
</MathContainer>

This means the price on that day is <InlineMath math="34\%" /> of the original price.

Now, we calculate the price of the biology book using the same percentage:

<MathContainer>
  <BlockMath math="\text{Biology Price} = 34\% \times 40,000" />
  <BlockMath math="\text{Biology Price} = \frac{34}{100} \times 40,000" />
  <BlockMath math="\text{Biology Price} = 34 \times 400" />
  <BlockMath math="\text{Biology Price} = 13,600" />
</MathContainer>

So, the price of the biology book on that day is <InlineMath math="13,600" /> rupiah.


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