Proportional Reasoning Math Example 1

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

Example 1

easy
If 3 notebooks cost \$7.50, how much do 7 notebooks cost?

Solution

  1. 1
    Because the relationship is proportional, first find the cost of 1 notebook.
  2. 2
    Find the unit price: \frac{7.50}{3} = \2.50$ per notebook.
  3. 3
    Multiply by 7: 2.50 \times 7 = \17.50$.

Answer

$17.50\$17.50
Proportional reasoning often starts by finding the unit rate, then scaling to the desired quantity.

About Proportional Reasoning

The ability to recognize and work with multiplicative relationships between quantities. If one quantity doubles, a proportional quantity also doubles β€” the ratio stays constant.

Learn more about Proportional Reasoning β†’

More Proportional Reasoning Examples

Example 2 medium

A recipe calls for 2 cups of flour for every 3 cups of sugar. If you use 9 cups of sugar, how many c

Example 3 medium

A map uses a scale of 1 cm : 25 km. Two cities are 7.5 cm apart on the map. What is the actual dista

Example 4 easy

A recipe that serves 4 people uses 10 cups of flour. How many cups are needed to serve 10 people?

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