Unit Rate Calculator with Fractions
This calculator helps you determine the unit rate when dealing with quantities expressed as fractions. A unit rate is the ratio of two different quantities where one of the quantities is 1. For example, miles per hour, dollars per pound, or tasks per day. When working with fractions, we often need to find out "how much of something per one unit of something else."
How to Calculate Unit Rate with Fractions
To find the unit rate when dealing with fractional quantities, you essentially divide the first quantity by the second quantity. Let's say your first quantity is represented by the fraction $\frac{a}{b}$ and your second quantity is represented by the fraction $\frac{c}{d}$.
The unit rate is calculated as:
Unit Rate = $\frac{\text{Quantity 1}}{\text{Quantity 2}}$ = $\frac{\frac{a}{b}}{\frac{c}{d}}$
To divide fractions, you invert the second fraction and multiply:
Unit Rate = $\frac{a}{b} \times \frac{d}{c} = \frac{a \times d}{b \times c}$
The result gives you the rate per single unit of the second quantity.
Example:
Suppose you can paint $\frac{3}{4}$ of a wall in $\frac{5}{6}$ of an hour. What is the unit rate of painting in walls per hour?
- Quantity 1: $\frac{3}{4}$ walls
- Quantity 2: $\frac{5}{6}$ hours
Using the formula:
Unit Rate = $\frac{\frac{3}{4}}{\frac{5}{6}} = \frac{3}{4} \times \frac{6}{5} = \frac{18}{20}$
Simplifying the fraction:
Unit Rate = $\frac{18}{20} = \frac{9}{10}$ walls per hour.
This means you can paint $\frac{9}{10}$ of a wall in one hour.
function calculateUnitRate() {
var numerator1 = parseFloat(document.getElementById("numerator1").value);
var denominator1 = parseFloat(document.getElementById("denominator1").value);
var numerator2 = parseFloat(document.getElementById("numerator2").value);
var denominator2 = parseFloat(document.getElementById("denominator2").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
if (isNaN(numerator1) || isNaN(denominator1) || isNaN(numerator2) || isNaN(denominator2)) {
resultDiv.innerHTML = "Please enter valid numbers for all fields.";
return;
}
if (denominator1 === 0 || denominator2 === 0) {
resultDiv.innerHTML = "Denominators cannot be zero.";
return;
}
// Calculate the first fraction: num1 / den1
var quantity1 = numerator1 / denominator1;
// Calculate the second fraction: num2 / den2
var quantity2 = numerator2 / denominator2;
// Calculate the unit rate: quantity1 / quantity2
if (quantity2 === 0) {
resultDiv.innerHTML = "The second quantity cannot be zero for unit rate calculation.";
return;
}
var unitRate = quantity1 / quantity2;
// To display the result as a fraction, we can use the simplified fraction from the formula:
// (numerator1 * denominator2) / (denominator1 * numerator2)
var resultNumerator = numerator1 * denominator2;
var resultDenominator = denominator1 * numerator2;
// Simple GCD function for fraction simplification
function gcd(a, b) {
return b === 0 ? a : gcd(b, a % b);
}
var commonDivisor = gcd(Math.abs(resultNumerator), Math.abs(resultDenominator));
var simplifiedNumerator = resultNumerator / commonDivisor;
var simplifiedDenominator = resultDenominator / commonDivisor;
// Ensure the sign is handled correctly and the denominator is positive if possible
if (simplifiedDenominator < 0) {
simplifiedNumerator = -simplifiedNumerator;
simplifiedDenominator = -simplifiedDenominator;
}
resultDiv.innerHTML = "Unit Rate: " + simplifiedNumerator + "/" + simplifiedDenominator;
resultDiv.innerHTML += " (or approximately " + unitRate.toFixed(4) + ")";
}
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