#78 One on top
Set by Howard Williams
It is possible to write any number as a sum of unit fractions (fractions with 1 on top) with different denominators. For example, 3/5 = 1/2 + 1/10.
Starting from the expression 1 = 1/6 + 1/6 + 1/6 + 1/6 + 1/6 + 1/6, can you combine the sixths together by adding, to make three unit fractions of different sizes that sum to 1?
If you begin instead with 12 twelfths, can you combine them to find a set of four different unit fractions that total 1?
How many other sets of four different unit fractions that add up to 1 can you find?
Solution next week
#77 Folded stacks
Solution
The three words are CARTHORSE, CAUTIONED and GNARLIEST.
For the third puzzle, the final step involves folding a 2-by-1 section in half, but tucking one half between the layers of the other.
Quick quiz #307
set by Corryn Wetzel
1 Which arcade game was inspired by H. G. Wells's The War of the Worlds?
2 Who proposed the theory of continental drift?
3 What was the first spacecraft to fly by Mercury?
4 Which chemical element has an atomic number of 92?
5 What is the clear, watery fluid in the front part of the eye called?
Quick quiz #307
Answers
1 Space Invaders
2 Alfred Wegener
3 Mariner 10
4 Uranium
5 Aqueous humour