Einstein Puzzle Collection

We are used to the idea that it is possible to sit still and pass time in a motionless manner. But this amazing planet of ours is very far from static. At all times, we are hurtling through the gulf of space at astonishing velocities. It may seem to casual thought that from the Sun’s viewpoint, all of Earth’s population is moving at the same speed. After all, our planet revolves around it at a steady 30km per second – anticlockwise, if we are looking from above the North Pole. However, there is another factor to consider. The Earth spins on its axis as it rotates, at a speed of around 28km per minute, if you are at the equator. You know, of course, that from the surface of the…

It is tempting, soothing even, to think of mathematics as a perfect edifice of logic and order. The truth, however, is that it is an art as well as a science, and it has places where absolutism breaks down. For this example, we will show that 0 = 1. First, however, I should point out that when adding a series of numbers, the associative law says that you may bracket the sums as you like without any effect. 1+2+3 = 1+ (2+3) = (1+2) +3. So, with that established, consider adding an infinite number of zeroes. No matter how much nothing you gather, you will still always have nothing. 0 = 0+0+0+0+0+… Since 1-1 = 0, you can replace each zero in your sum, like so: 0 = (1-1)+(1-1)+(1-1)+(1-1)+(1-1)+… From…

The English mathematician and author Lewis Carroll devised a series of excellent logical problems designed to illustrate and test deductive reasoning. Several statements are given below. You may assume – for the duration of this problem – that they are absolutely true in all particulars. From that assumption, you should be able to provide an answer to the question that follows. I dislike things that cannot be put to use as a bridge. Sunset clouds are unable to bear my weight. The only subjects I enjoy poems about are things which I would welcome as a gift. Anything which can be used as a bridge is able to bear my weight. I would not accept a gift of a thing I disliked. Would I enjoy a poem about sunset clouds?…

Many numbers, particularly in the lower orders, can make a good claim for being of particular interest. It is in the realm of square numbers that 48 is of especial curiosity. If you add 1 to it, you get a square number [48+1 = 49 = 7x7], and if instead you halve it and add 1 to the result, you get a different square number [(48/2 = 24)+1 = 25 = 5x5]. Individually, the two conditions are trivially common, but taken together this way, they are less so. In fact, 48 is the smallest number to satisfy both conditions. Can you find the next smallest to do so? Solution on page 84…

The puzzle below holds a well-known quotation. Although the words in each line remain in the correct order, all punctuation has been removed, and the lines themselves have been jumbled up. Are you able to piece the original quotation back together? LIKE AN HOUR THAT’S RELATIVITY LIKE A SECOND WHEN NICE GIRL AN HOUR SEEMS HOT CINDER A SECOND SEEMS WHEN YOU ARE COURTING A YOU SIT ON A RED ALBERT EINSTEIN Solution on page 84 “Whoever is careless with the truth in small matters cannot be trusted with important matters.”ALBERT EINSTEIN…

This mathematical party game was devised in the thirteenth century by the Italian mathematician Leonardo Pisano, known to the modern world as Fibonacci. His work on the mathematical systems helped to set up the Renaissance, but the matter we will address here is less weighty. Between two and nine people sit in a line, and together, they secretly conspire to select one of their number. This person picks a finger joint of one of their hands, either where a ring is being worn, or where the volunteer nominates as a spot that he or she would like to wear a ring. The volunteer then takes their position in the line, doubles it, adds 5, multiplies by 5, and then adds 10 to this total. Then the number of the ring-bearing…