A roll of stickers repeats the pattern star ✦, moon ☾, cloud ☁, then star ✦ again, and so on, in that order. Ben cut out a length of the roll that contains exactly 27 moons ☾. What is the greatest possible number of stars ✦ in the length he cut out?
Need a hint?
Draw the pattern and mark where each moon sits. Think about which stars can sit before the first moon and after the last moon.
Worked answer
- Each repeat of the pattern has exactly one moon and one star.
- Between two consecutive moons there is exactly one star.
- 27 moons have 26 gaps between them, so 26 stars lie between the first and last moon.
- Add one star before the first moon and one star after the last moon, which the greatest length can include.
- 26 + 1 + 1 = 28 stars.
The mistake this question tests
Calculation slip
Pupils often count only the stars between the moons (26) or multiply 27 by the number of stars per repeat, forgetting that the ends of the cut length can also include stars.
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