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Do Unto Caesar

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 assets of the players at the beginning of the evening?

Oh for the Mathematics of Yesteryear

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 days against the siege of the enemy?

Racing Odds

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?

How Big?

Age 11 to 14 Challenge Level:

The following solution came from Alistair Jacklin, class 9S, King Edward Camp Hill School for Boys. Kang Hong Joo of The Chinese High School, Singapore and Neil Wright of Madras College, St Andrew's and Jessica Zhang, Woodbridge School, Essex used the same method.

how big diagram

The first thing I did was to split the large triangle into 3 sections, a square and 2 smaller triangles. Next I then worked out the area of the large triangle using the formula:-

Height * Width * 0.5 = area of the triangle
3 * 4 * 0.5 = area of a triangle
6 = area of a large triangle

With this I used a formula to show the area of this triangle by adding the areas of the other parts:

x 2 + 0.5 x(3 - x) + 0.5 x(4 - x) = 6.

The formula is then simplified in several easy steps to give:-

x 2 + 1.5 x - 0.5 x 2 + 2 x - 0.5 x 2 = 6
3.5 x = 6
x = 12/7

The area of the square is then x 2 = 144/49 exactly. Rounded to three decimal places this is 2.938.