Proportionality Math Example 1

Follow the full solution, then compare it with the other examples linked below.

Example 1

easy
A car travels 150150 miles in 33 hours at constant speed. How far will it travel in 55 hours?

Solution

  1. 1
    Find the unit rate (speed): 150 miles3 hours=50\dfrac{150 \text{ miles}}{3 \text{ hours}} = 50 mph.
  2. 2
    Distance in 55 hours: 50×5=25050 \times 5 = 250 miles.
  3. 3
    Alternatively, set up a proportion: 1503=d5\dfrac{150}{3} = \dfrac{d}{5}, so d=150×53=250d = \dfrac{150 \times 5}{3} = 250 miles.

Answer

The car travels 250250 miles in 55 hours.
Two quantities are proportional when their ratio is constant. Here, distance and time have a constant ratio (speed). Setting up a proportion or multiplying by the unit rate both give the same result.

About Proportionality

A relationship where two quantities maintain a constant ratio: doubling one always doubles the other, giving y=kxy = kx.

Learn more about Proportionality →

More Proportionality Examples

Example 2 medium

The table shows: [formula]; [formula]; [formula]. Determine whether [formula] is proportional to [fo

Example 3 easy

If [formula] apples cost [formula]3.60[formula]20$ apples cost?

Example 4 medium

Is the relationship [formula] proportional? Is [formula] proportional? Explain.

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