Sunday Times Teaser 2548 – Planetary Line
by Danny Roth
Published: 24 July 2011 (link)
George and Martha are studying a far- off galaxy consisting of 10 planets circling a sun clockwise, all in the same plane. The planets are Unimus (taking one year to circle the sun), Dubious (two years), Tertius (three years), and so on up to Decimus (10 years). At one instant today the sun and all 10 planets were in one straight line. Martha said it will be ages before that happens again. “Don’t let’s be greedy,” said George. “How long must we wait until at least nine planets and the sun are in a straight line?”
How long must they wait?