Walking to school
There are 60 students in a class. 35% of them walk to school, and 10 ride bikes. How many students walk to school?
Asked: how many students walk (students). Is a: Find a percent of a number. Answer: 21 students.
| Phrase | Value | Counts | Needed? |
|---|---|---|---|
| “60 students” | 60 students | the class | yes |
| “35% of them walk” | 35 percent | walkers | yes |
| “10 ride bikes” | 10 students | bike riders | no |
| Decision | Concept | Correct | Traps → wrong answer |
|---|---|---|---|
| What kind of question is this? | Recognize the question type | 35% of a group: a percent of a number | — |
| 35% of what? | Find the pair that forms the ratio | Of all 60 students | Of the 10 bike riders → 3.5 |
| What about the 10 bike riders? | Ignore numbers that don’t matter | Not needed | Take them out first → 17.5 |
The graph starts at the story. The Extract frame holds the decisions; red dashed arrows leave a decision for each trap and run to the wrong answer it produces. The thick green arrow carries the extracted numbers into the question, drawn exactly as on the question’s own page. Any follow-up step comes after, then the answer in the story’s terms. The legend is at the bottom.
| Trap | Mistake | Leads to | Caught by the answer? | Gives itself away with |
|---|---|---|---|---|
| Find the pair that forms the ratio | Takes 35% of the 10 bike riders. | 3.5 | yes | 10 ÷ 100 = 0.1, 35 × 10 = 350, 10 ÷ 10 = 1 |
| Ignore numbers that don’t matter | Takes the 10 bike riders out of the class first. | 17.5 | yes | 60 − 10 = 50, 50 ÷ 100 = 0.5, 35 × 50 = 1750, 50 ÷ 10 = 5 |