An article for teachers which discusses the differences between
ratio and proportion, and invites readers to contribute their own
In a race the odds are: 2 to 1 against the rhinoceros winning and 3 to 2 against the hippopotamus winning. What are the odds against the elephant winning if the race is fair?
Is it always possible to combine two paints made up in the ratios
1:x and 1:y and turn them into paint made up in the ratio a:b ? Can
you find an efficent way of doing this?
A decorator can buy pink paint from two manufacturers. What is the
least number he would need of each type in order to produce
different shades of pink.
A farmer is supplying a mix of seeds, nuts and dried apricots to a
manufacturer of crunchy cereal bars. What combination of
ingredients costing £5 per kg could he supply?
Use the ratio of cashew nuts to peanuts to find out how many
peanuts Rachel has. What would the ratio be if Rachel and Marianne
mixed their bags?
A garrison of 600 men has just enough bread ... but, with the news
that the enemy was planning an attack... How many ounces of bread a
day must each man in the garrison be allowed, to hold out 45. . . .
Read all about the number pi and the mathematicians who have tried to find out its value as accurately as possible.
Match pairs of cards so that they have equivalent ratios.
Points P, Q, R and S each divide the sides AB, BC, CD and DA respectively in the ratio of 2 : 1. Join the points. What is the area of the parallelogram PQRS in relation to the original rectangle?
At the beginning of the night three poker players; Alan, Bernie and Craig had money in the ratios 7 : 6 : 5. At the end of the night the ratio was 6 : 5 : 4. One of them won $1 200. What were the. . . .
A Sudoku with clues as ratios or fractions.
Use the Cuisenaire rods environment to investigate ratio. Can you
find pairs of rods in the ratio 3:2? How about 9:6?
Can you work out which drink has the stronger flavour?
A card pairing game involving knowledge of simple ratio.
A Sudoku with clues as ratios.
If the sides of the triangle in the diagram are 3, 4 and 5, what is
the area of the shaded square?
The triangles in these sets are similar - can you work out the
lengths of the sides which have question marks?