Question

A supermarket awards coupons depending on how much a customer spends on groceries. For example, if you spend \(\$ 50\), you will get a coupon worth cight percent of that amount. The following table shows the percent used to calculate the coupon awarded for different amounts spent. Write a program that calculates and prints the value of the coupon a person can receive based on groceries purchased. Here is a sample run: Please enter the cost of your groceries: 14 You win a discount coupon of \(\$ 1.12\). ( \(8 x\) of your purchase)

Short answer

Coupon value is calculated by multiplying groceries cost by the applicable percentage from the table.

Step-by-step solution

Understand the Problem

The problem asks us to create a program that calculates the value of a coupon based on how much a customer spends on groceries. Different spending amounts correspond to different percentages for coupon calculation.

Review the Coupon Table

Review the table provided in the problem to understand which percentage applies to different spending intervals. For example, spending exactly $50 means using an 8% calculation.

Implement the Program Structure

Write a function that takes the cost of groceries as input and determines the correct percentage for the discount based on that input.

Calculate the Coupon Value

Multiply the cost of groceries by the applicable percentage to find the coupon value. For an expenditure of $14, multiply by 0.08 (8%) to calculate the discount.

Output the Result

Print the coupon value formatted to two decimal places, and state what percentage of the purchase it represents.

Key concepts

Conditional Statements

Conditional statements, like "if" and "else" in Python, allow for decision-making in a program. When building a program that decides on a coupon percentage based on spending, these conditional statements become essential. Here’s how they work:

In simplest terms, a conditional statement will check a condition and execute a block of code accordingly. For instance, if spending >= 50: means "if the spending is equal to or more than $50, then...". These conditional statements act like guiding lights for the program. They tell it what actions to perform and what calculations to make based on the input it receives.

When you write a program for coupon calculations, you typically have multiple conditions. Each condition corresponds to a different spending interval and percentage.

• Use if to check the first condition.
• Use elif for any subsequent conditions.
• Use else to define what happens when none of the previous conditions are true.

These conditional branches ensure your program accurately calculates the coupon value each time based on how much is spent.

Functions in Python

Functions are integral to programming in Python. They allow you to bundle code into reusable blocks. By defining all the steps necessary to calculate a coupon in one function, you make your program more organized and easier to maintain.

Here’s how functions work:

• Define a function using the def keyword.
• Include parameters in parentheses, which act as placeholders for values we will pass to the function.
• Write the code inside the function body that performs the desired task.

For example, to calculate a coupon, you might define a function like this:
def calculate_coupon(cost):
This function might take the cost of groceries as its parameter and return the calculated coupon value based on that cost. It makes future updates easier, as you can adjust your logic without changing the code that calls this function.
Using functions not only makes your code reusable and clean but also allows you to perform specific computations in isolation, which is especially useful in larger programs.

Percentage Calculations

In programming, percentage calculations are common in tasks involving discounts, taxes, and interest rates, much like calculating grocery coupons. Understanding how to handle these calculations accurately is vital for generating the correct results.

To calculate a percentage of a given number, you multiply the number by the percentage (expressed as a decimal). For instance, to find 8% of a $50 purchase, you multiply 50 by 0.08. It's essential to remember to use decimal form for percentages, as this ensures Python performs the multiplication correctly.

Let’s break it down:

• Convert the percentage to a decimal by dividing by 100 (e.g., 8% becomes 0.08).
• Multiply the spending amount by this decimal to find the coupon value.

Once calculated, it's good to format the result to two decimal places when printing it. This ensures clarity and precision, especially in financial calculations. By understanding these basics of percentage calculations, programming exercises like this become straightforward and logical.