October 1999, All Stages

Problems

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Three by Three

Stage: 1 Challenge Level: Challenge Level:2 Challenge Level:2

Arrange 3 red, 3 blue and 3 yellow counters into a three-by-three square grid, so that there is only one of each colour in every row and every column

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The Amazing Splitting Plant

Stage: 1 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Can you work out how many flowers there will be on the Amazing Splitting Plant after it has been growing for six weeks?

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Clever Keys

Stage: 2 Short Challenge Level: Challenge Level:1

On a calculator, make 15 by using only the 2 key and any of the four operations keys. How many ways can you find to do it?

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Seating Arrangements

Stage: 2 Challenge Level: Challenge Level:1

Sitting around a table are three girls and three boys. Use the clues to work out were each person is sitting.

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Cat Food

Stage: 2 Challenge Level: Challenge Level:1

Sam sets up displays of cat food in his shop in triangular stacks. If Felix buys some, then how can Sam arrange the remaining cans in triangular stacks?

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World of Tan 1 - Granma T

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2

Can you fit the tangram pieces into the outline of Granma T?

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Arranging the Tables

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2

There are 44 people coming to a dinner party. There are 15 square tables that seat 4 people. Find a way to seat the 44 people using all 15 tables, with no empty places.

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Pouring the Punch Drink

Stage: 2 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

There are 4 jugs which hold 9 litres, 7 litres, 4 litres and 2 litres. Find a way to pour 9 litres of drink from one jug to another until you are left with exactly 3 litres in three of the jugs.

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Sometimes We Lose Things

Stage: 2 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Well now, what would happen if we lost all the nines in our number system? Have a go at writing the numbers out in this way and have a look at the multiplications table.

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Like Powers

Stage: 3 Challenge Level: Challenge Level:1

Investigate $1^n + 19^n + 20^n + 51^n + 57^n + 80^n + 82^n $ and $2^n + 12^n + 31^n + 40^n + 69^n + 71^n + 85^n$ for different values of n.

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All Square

Stage: 3 Challenge Level: Challenge Level:2 Challenge Level:2

Solve the system of equations xy = 1 yz = 4 zx = 9

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Thirty Six Exactly

Stage: 3 Challenge Level: Challenge Level:2 Challenge Level:2

The number 12 = 2^2 3 has 6 factors. What is the smallest natural number with exactly 36 factors?

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Three Four Five

Stage: 4 Challenge Level: Challenge Level:2 Challenge Level:2

Two semi-circles (each of radius 1/2) touch each other, and a semi-circle of radius 1 touches both of them. Find the radius of the circle which touches all three semi-circles.

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Rachel's Problem

Stage: 4 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Is it true that $99^n$ has 2n digits and $999^n$ has 3n digits? Investigate!

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Lunar Leaper

Stage: 5 Challenge Level: Challenge Level:1

Gravity on the Moon is about 1/6th that on the Earth. A pole-vaulter 2 metres tall can clear a 5 metres pole on the Earth. How high a pole could he clear on the Moon?

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Old Nuts

Stage: 5 Challenge Level: Challenge Level:1

In turn 4 people throw away three nuts from a pile and hide a quarter of the remainder finally leaving a multiple of 4 nuts. How many nuts were at the start?

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Absurdity Again

Stage: 5 Challenge Level: Challenge Level:1

What is the value of the integers a and b where sqrt(8-4sqrt3) = sqrt a - sqrt b?

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Logosquares

Stage: 5 Challenge Level: Challenge Level:1

Ten squares form regular rings either with adjacent or opposite vertices touching. Calculate the inner and outer radii of the rings that surround the squares.