An easy question on meeting for P3–P4, with a step-by-step solution, diagrams and the answer. The basis of journey problems: meeting and catching up appear in the Hua Xia Cup's P4 to P6 qualifying rounds and finals.
The question
Ming and May stand at opposite ends of the playground, 15 m apart.
They set off at the same moment and run straight towards each other.
Ming runs 3 m a second and May 2 m a second.
After how many seconds do they meet?
Show the hints (2)
💡Hint 1: Each second, how much shorter does the distance between them get?
💡Hint 2: Together they have to close all 15 m.
Worked solution
Have a go first, then read the solution step by step.
1.Each second Ming runs 3 m and May 2 m: together they close 3 + 2 = 5 m.
2.The 15 m gap shrinks by 5 m a second: 15 ÷ 5 = 3, so they meet after 3 seconds.
⚠️Common mistake: dividing by one runner's speed. Both are running, so they close the gap together.
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