Simultaneous equations

problem

How Many Balls?

Age

16 to 18

Challenge level

A bag contains red and blue balls. You are told the probabilities of drawing certain combinations of balls. Find how many red and how many blue balls there are in the bag.
problem

Graphs of Changing Areas

Age

16 to 18

Challenge level

Use graphs to gain insights into an area and perimeter problem, or use your knowledge of area and perimeter to gain insights into the graphs...
problem

Real(ly) Numbers

Age

16 to 18

Challenge level

If x, y and z are real numbers such that: x + y + z = 5 and xy + yz + zx = 3. What is the largest value that any of the numbers can have?
problem

Cobalt Decay

Age

16 to 18

Challenge level

Investigate the effects of the half-lifes of the isotopes of cobalt on the mass of a mystery lump of the element.
article
A Method of Defining Coefficients in the Equations of Chemical Reactions

A simple method of defining the coefficients in the equations of chemical reactions with the help of a system of linear algebraic equations.