PHP Exercises: Compute the amount of the debt in n months

Last update on May 26 2025 13:17:15 (UTC/GMT +8 hours)

50. Debt Calculation in n Months

Write a PHP program to compute the amount of the debt in n months. The borrowing amount is $100,000 and the loan adds 5% interest of the debt and rounds it to the nearest 1,000 above month by month.

Input:
An integer n (0 ≤ n ≤ 100) .

Sample Solution:

PHP Code:

<?php
// Read an integer from standard input representing the number of years
fscanf(STDIN, '%d', $n);

// Initialize the initial debt amount
$debt = 100000;

// Loop through each year to calculate the debt amount after each year
for ($i = 0; $i < $n; $i++) {
    // Calculate the new debt amount after applying a 5% increase and rounding to the nearest thousand
    $debt = ceil(($debt * 1.05) / 1000) * 1000;
}

// Print the final amount of debt
echo "\nAmount of debt: ";
echo $debt . PHP_EOL;

?>

Explanation:

Reading Input:

The program reads an integer from standard input (STDIN) that represents the number of years ($n) using fscanf(STDIN, '%d', $n);.

Initializing Debt:

A variable $debt is initialized to 100,000, representing the starting amount of debt.

Loop Through Years:

A for loop runs from 0 to $n - 1, iterating over each year to calculate the debt for each year.

Calculating New Debt:

Inside the loop, the new debt amount is calculated by applying a 5% increase:

($debt * 1.05) calculates the increased debt.
This amount is then divided by 1000, rounded up to the nearest whole number using ceil(), and multiplied back by 1000 to round to the nearest thousand.

Outputting Final Debt:

After the loop completes, the final amount of debt is printed to the standard output, preceded by the message "Amount of debt: ".

Output:

Amount of debt: 137000

Flowchart:

For more Practice: Solve these Related Problems:

Write a PHP script to simulate monthly compound interest on a debt with rounding to the nearest thousand.
Write a PHP function to model a loan’s growth over n months, incorporating interest and custom rounding rules.
Write a PHP script to calculate debt after successive monthly increments with a compounded interest rate.
Write a PHP script to verify monthly debt calculations and output the final amount with proper rounding.

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PHP Code Editor:

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