Proportional relationships can be used to solve real-world p...

Question Analysis
This question tests the student's understanding of proportional relationships and their ability to solve real-world problems using ratios.

Key Concept Explanation
Proportional relationships involve setting up and solving proportions to find unknown quantities.

Step-by-step Solution
1. Set up the proportion: , where is the number of blue marbles.
2. Cross-multiply to solve for :