Problem 5 · 2019 AMC 8
Medium
Ratios, Rates & Proportions
distance-speed-timegraph-reading
Show answer
Answer: B — Graph (B).
Show hints
Hint 1 of 2
On a distance-vs-time graph, steepness is speed and a flat stretch means "not moving." Translate the story into two shapes, then find the graph that has both.
Still stuck? Show hint 2 →
Hint 2 of 2
Two clues must both show up: the hare's line has a flat middle (the nap), and the tortoise's line hits the finish height at an earlier time than the hare's. Use these to eliminate, not to eyeball.
Show solution
Approach: read slopes as speeds, then use two distinguishing features
- Slope = speed. The hare runs (steep), naps (flat), then runs again (steep) — so the hare's curve is the one with a horizontal plateau in the middle.
- The tortoise moves at one steady slow pace, a single straight gentle line. The crucial detail: "the tortoise was already there," so the tortoise's line reaches the top (finish distance) at a smaller time than the hare's.
- Only graph (B) shows the napping plateau AND the tortoise finishing first.
- Why this transfers: match graphs to stories by listing 2–3 testable features (a flat part, who reaches the top first, where lines cross) and eliminate — trying to read the whole picture at once is where mistakes sneak in.
Mark:
· log in to save