Proportional Reasoning Math Example 2

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

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 cups of flour do you need?

Solution

  1. 1
    Set up the proportion: 23=x9\frac{2}{3} = \frac{x}{9}.
  2. 2
    Cross-multiply: 2×9=3×x2 \times 9 = 3 \times x, so 18=3x18 = 3x.
  3. 3
    Solve: x=183=6x = \frac{18}{3} = 6.

Answer

6 cups of flour6 \text{ cups of flour}
Set up a proportion with matching units and cross-multiply to solve for the unknown. Verify that the ratio 69=23\frac{6}{9} = \frac{2}{3} confirms the answer.

About Proportional Reasoning

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

Learn more about Proportional Reasoning →

More Proportional Reasoning Examples

Example 1 easy

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

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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