A hard question on queues for P4–P5, with a step-by-step solution, diagrams and the answer. Queue questions are already in the Hua Xia Cup's P1 and P2 first rounds, and the P4 papers add square formations.
The question
On Sunday morning, people queue in single file outside a cha chaan teng.
The number of people in front of Ming is exactly 2 times the number behind him.
May is behind Ming, with 2 people between them.
There is 1 more person behind May.
How many people are in the queue?
Show the hints (3)
💡Hint 1: First count the people behind Ming: who are they?
💡Hint 2: Behind Ming there are three parts: those between, May, and those behind May.
💡Hint 3: There are 4 behind Ming, and 2 times as many in front. Who is still uncounted?
Worked solution
Have a go first, then read the solution step by step.
1.Behind Ming: 2 + 1 (May) + 1 = 4.
2.In front of Ming: 4 × 2 = 8.
3.The queue: 8 + 1 (Ming) + 4 = 13.
⚠️Common mistake: counting only 2 + 1 = 3 behind Ming, leaving May out.
Play more like this in Numsprite (unlimited questions, instant marking) →A free maths game: every level free from Easy to Expert (★ to ★★★★), unlimited questions, no download