30 passengers are in a sinking ship. They all stand in a circle. Every 9th passenger goes overboard. The lifeboat holds 15. Where are the 15 lucky positions in the circle?

• 1 2 3 4 10 11 13 14 15 17 20 21 25 28 29
• 12 years agoHelpfull: Yes(0) No(0)
• Lets arrange the 30 passengers in a circle from 1-30. Then lets encircle every 9th number after repeated iterations (every encircled number represents a passenger going overboard). Continue encircling the number unless until 15 UN CIRCLED numbers (passengers) remain. If we follow this sequence, the encircling of following numbers will take place in order - 9, 18, 27, 6, 16, 26, 7, 19, 30, 12, 24, 8, 22, 5, 23. All these numbers/passengers are going overboard. So, the 15 lucky positions are: 1, 2, 3, 4, 10, 11, 13, 14, 15, 17, 20, 21, 25, 28, 29 ! Hope this is correct
• 10 years agoHelpfull: Yes(0) No(0)