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Overturning Fracsum
Solve the system of equations to find the values of x, y and z: xy/(x+y)=1/2, yz/(y+z)=1/3, zx/(z+x)=1/7
Rudolff's Problem
A group of 20 people pay a total of £20 to see an exhibition. The admission price is £3 for men, £2 for women and 50p for children. How many men, women and children are there in the group?
Age 14 to 16
Challenge Level
Four straight lines have the following equations:
$$\begin{align} 3x+8y&=59 \\ x-2y&=1 \\ y-4x&=3 \\ 3y+2x &= -19 \end{align}$$
How many points of intersections do you expect there to be?
Three of the four lines enclose a triangle which only has negative co-ordinates for all points on that triangle.
Which three lines?
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NRICH is part of the family of activities in the Millennium Mathematics Project.
NRICH is part of the family of activities in the Millennium Mathematics Project.