Ratio and proportion

There are 112 NRICH Mathematical resources connected to Ratio and proportion
Ratio Sudoku 1
problem
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Ratio sudoku 1

Age
11 to 16
Challenge level
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A Sudoku with clues as ratios.
Two Ladders
problem
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Two ladders

Age
14 to 16
Challenge level
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Two ladders are propped up against facing walls. The end of the first ladder is 10 metres above the foot of the first wall. The end of the second ladder is 5 metres above the foot of the second wall. At what height do the ladders cross?
Rule of Three
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Rule of three

Age
11 to 14
Challenge level
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If it takes four men one day to build a wall, how long does it take 60,000 men to build a similar wall?
Pumpkin Pie Problem
problem
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Pumpkin pie problem

Age
7 to 11
Challenge level
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Peter wanted to make two pies for a party. His mother had a recipe for him to use. However, she always made 80 pies at a time. Did Peter have enough ingredients to make two pumpkin pies?

Trapezium Four
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Trapezium four

Age
14 to 16
Challenge level
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The diagonals of a trapezium divide it into four parts. Can you create a trapezium where three of those parts are equal in area?
Triangle in a Triangle
problem
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Triangle in a triangle

Age
14 to 16
Challenge level
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Can you work out the fraction of the original triangle that is covered by the inner triangle?
Mixing Lemonade
problem
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Mixing lemonade

Age
11 to 14
Challenge level
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Can you work out which drink has the stronger flavour?

Ratios and Dilutions
problem
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Ratios and dilutions

Age
14 to 16
Challenge level
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Scientists often require solutions which are diluted to a particular concentration. In this problem, you can explore the mathematics of simple dilutions
One and three
problem
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One and three

Age
14 to 16
Challenge level
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Two motorboats travelling up and down a lake at constant speeds leave opposite ends A and B at the same instant, passing each other, for the first time 600 metres from A, and on their return, 400 metres from B. How long is the lake?
Blackcurrantiest
problem
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Blackcurrantiest

Age
5 to 7
Challenge level
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Can you decide whose drink has the strongest blackcurrant flavour from these pictures?