Original SAT-style linear-equation check
Students practising algebra reasoning without copied exam material
- Skill: interpret a linear relationship
- Four answer options
- Explanation and misconception required
Question
A fictional delivery service charges a fixed fee plus the same amount per kilometre. A 4 km trip costs $14 and an 8 km trip costs $22. Which equation gives cost c for distance d?
Options
- A. c = 2d + 6
- B. c = 4d − 2
- C. c = 6d + 2
- D. c = 8d + 14
Answer and explanation
A. The cost increases $8 across 4 km, so the rate is $2/km; substituting d = 4 gives the $6 fixed fee.
Targeted misconception
Using one observed total as the rate or ignoring the fixed fee. Difficulty: medium.
