Chapter 16: Problem 13
A \(30 \%\) discount reduces the price of a commodity by $$\$ 90$$. If the discount is reduced to \(20 \%\), then the price of the commodity will be (A) $$\$ 180$$ (B) $$\$ 210$$ (C) $$\$ 240$$ (D) $$\$ 270$$ (E) $$\$ 300$$
Short Answer
Expert verified
The price will be $240, choice (C).
Step by step solution
01
Understand the relationship between discount and original price
Given a 30% discount reduces the price of a commodity by $90. This means 30% of the original price equals $90. Let's find the original price using the relationship that 0.3 times the original price equals $90.
02
Calculate the original price
Let \( x \) be the original price. From Step 1, we have \( 0.3x = 90 \). Solving for \( x \), we divide both sides by 0.3:\[ x = \frac{90}{0.3} = 300 \]
03
Calculate the new price with a 20% discount
The problem states that the discount is reduced to 20%. Hence, the discounted amount is now 20% of the original price. Calculate 20% of the original price:\[ 0.2 \times 300 = 60 \]
04
Calculate the selling price with the new discount
Subtract the 20% discount from the original price to find the new selling price:\[ 300 - 60 = 240 \]
05
Identify the correct answer from the options
From Step 4, we found the new selling price is $240. Therefore, the correct answer is (C) $240.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Percentage Discount
In math, understanding percentage discounts is vital for problems involving price reductions. A percentage discount is the reduction in price expressed as a percentage of the original price. It helps quantify how much cheaper an item is compared to its original selling price.
Here's how it works: if you have a 30% discount on an item, it means you're paying 70% of the original price. The 30% signifies the amount deducted.
Here's how it works: if you have a 30% discount on an item, it means you're paying 70% of the original price. The 30% signifies the amount deducted.
- 30% discount means you pay 70% of the original price.
- 20% discount means you pay 80% of the original price.
Original Price Calculation
Finding the original price is crucial in solving discount-related math problems. Once you know the discount and the amount it translates to, you can determine the original price.
To calculate the original price from a percentage discount, first express the discount amount as an equation. In our example, 30% of the original price equals \(90, or mathematically stated, as: \( 0.3 \times \text{original price} = 90 \).
To isolate the original price variable, divide both sides by the discount percentage in decimal form:
To calculate the original price from a percentage discount, first express the discount amount as an equation. In our example, 30% of the original price equals \(90, or mathematically stated, as: \( 0.3 \times \text{original price} = 90 \).
To isolate the original price variable, divide both sides by the discount percentage in decimal form:
- \( \frac{90}{0.3} = 300 \)
Step-by-Step Solution
When tackling math problems, a step-by-step solution is like your guiding map, ensuring you don't get lost.
Start by understanding the relationship between discount and price. Identify given data and relationships. Here, a 30% discount equals \(90.
Start by understanding the relationship between discount and price. Identify given data and relationships. Here, a 30% discount equals \(90.
- Step 1: Establish the equation: \( 0.3x = 90 \).
- Step 2: Solve for \( x \) by dividing both sides by 0.3, resulting in an original price of \)300.
- Step 3: With the new 20% discount, calculate how much will be deducted from \(300: \( 0.2 \times 300 = 60 \).
- Step 4: Subtract the \)60 discount from \(300.
- Step 5: Verify and choose the correct answer from given options: \)240.
Solving Equations
Solving equations is a fundamental skill in math that applies to numerous problems, including those with discounts. It involves finding the value of a variable that satisfies the equation.
In discount problems, equations often illustrate the relationship between the discount percentage and the original price. For instance, the equation \( 0.3x = 90 \) was essential to finding the original price. By solving it, you isolate \( x \).
To solve, perform simple arithmetic operations to both sides of the equation:
In discount problems, equations often illustrate the relationship between the discount percentage and the original price. For instance, the equation \( 0.3x = 90 \) was essential to finding the original price. By solving it, you isolate \( x \).
To solve, perform simple arithmetic operations to both sides of the equation:
- Divide both sides by 0.3: \( x = \frac{90}{0.3} \).