Simultaneous equations

problem

Double Time

Age

16 to 18

Challenge level

2 out of 3

Crack this code which depends on taking pairs of letters and using two simultaneous relations and modulus arithmetic to encode the message.
problem

Pareq Calc

Age

14 to 16

Challenge level

3 out of 3

Triangle ABC is an equilateral triangle with three parallel lines going through the vertices. Calculate the length of the sides of the triangle if the perpendicular distances between the parallel lines are 1 unit and 2 units.
problem

Letter Land

Age

11 to 14

Challenge level

1 out of 3

If: A + C = A; F x D = F; B - G = G; A + H = E; B / H = G; E - G = F and A-H represent the numbers from 0 to 7 Find the values of A, B, C, D, E, F and H.
problem

Nine, Ten and One

Age

11 to 14

Challenge level

1 out of 3

Can you find the value of t in these equations?
problem

In Sum-Mary

Age

11 to 14

Challenge level

1 out of 3

What does the sum of these three numbers tell us about their product?
problem

The Simple Life

Age

11 to 14

Challenge level

2 out of 3

The answer is $5x+8y$... What was the question?
problem

Not a Polite Question

Age

11 to 14

Challenge level

2 out of 3

When asked how old she was, the teacher replied: My age in years is not prime but odd and when reversed and added to my age you have a perfect square...
problem

Whole Numbers Only

Age

11 to 14

Challenge level

2 out of 3

Can you work out how many of each kind of pencil this student bought?
problem

Sweet Shop

Age

11 to 14

Challenge level

2 out of 3

In the sweet shop, there are cola bottles, mini eggs, marshmallow twists and lollipops, all costing under 50p. How could Nathan spend all his money?
problem

Children at Large

Age

11 to 14

Challenge level

2 out of 3

There are four children in a family, two girls, Kate and Sally, and two boys, Tom and Ben. How old are the children?