#70 Taking the biscuit
Alpha and Betty play a rather greedy game. There are eight digestive biscuits in one jar, and four rich tea biscuits in another. Each player can collect biscuits in one of two ways. They either: 鈥� Take any number of biscuits from one jar, or 鈥� Take an equal number of biscuits from both jars.
The player who takes the last biscuit wins the game and gets to keep all the biscuits. Alpha is set to go first. What biscuit or biscuits should she take?
Answer next week
#69 Cutting the flag
Solution
Three-fifths of the trapezium is blue, the same proportion as for the uncut flag.
One way to see this is to make a copy of the trapezium, rotate it by 180 degrees and place it next to the first. It will form a parallelogram made of five stripes, now all of equal length. Three-fifths of the parallelogram is blue, and because the two trapezia were identical, they will also have the same fraction of blue.
Quick quiz #62
1 The archetypal anabolic steroid has the chemical formula C19 H28 O2 and is better known as what?
2 With what theory in Earth science is the name Alfred Wegener closely associated?
3 The lepidopterans Pieris rapae and Pieris brassicae are both sometimes given what name, a commentary on their colour and favoured foodstuff?
4 The Large Synoptic Survey Telescope project in Chile was recently renamed to honour which astronomer, whose galactic observations in the 1970s and 1980s sent cosmology into a spin?
5 What name is given to the tiny air sacs at the end of your lung鈥檚 bronchioles that exchange oxygen and carbon dioxide as you breathe?
Answers on page 54
Answers
1 Testosterone
2 Continental drift, or what is now plate tectonics; Wegener first suggested that Earth鈥檚 continents were moving relative to one another in 1912
3 Cabbage white butterfly; for those that distinguish, P. rapae is the small white, P. brassicae the large white
4 Vera Rubin. Her studies of rotating galaxies suggested unseen 鈥渄ark鈥� matter must far outweigh normal matter within them
5 Alveoli