The digits 1 to 9 are placed in the square as shown. Starting at the star, follow a line and write the digits that it passes. The example gives 42685. Which option gives the greatest number?
Mary folded a piece of paper exactly in half, then exactly in half again, obtaining the right triangle shown. Which of P, Q and R could be the original paper?
The map shows stations A, B and C. The tours A–Zoo–Port–A, B–Park–Zoo–B and C–Port–Park–C are 10 km, 12 km and 13 km. The tour Zoo–Park–Port–Zoo is 15 km. How long is the shortest tour A–B–C–A?
Rosa wants to enter at one arrow, follow the line and leave at the other arrow. Which piece cannot be put in the middle to make this possible? Pieces may be rotated.
A triangular pyramid is made of 10 identical balls. Two balls bear each of the letters A, B, C, D and E. The three side views are shown. What letter is on the ball with the question mark?
Ronja has four white tokens and Wanja four gray tokens. They alternate placing one token onto either of two piles, with Ronja first. Which pair of piles cannot be made?
A four-digit bicycle lock uses digits 0–9 on each wheel. Starting from the correct combination, my brother turned every wheel the same amount in the same direction; it now shows 6348. Which option cannot have been the correct combination?
Two trains leave X and Y simultaneously on one track, at constant speeds. The X-to-Y train needs 180 minutes for the full trip; the Y-to-X train needs 60 minutes. Where should a short double-track section be built so they can pass safely?