You may also like

Mediant Madness

Kyle and his teacher disagree about his test score - who is right?

Marathon Mission

Minnie trained more for the London Marathon this year, so her speed increased. By what percentage did her time decrease?

Tyneside Average Speed

Can you work out the average speed of the van?

For Richer for Poorer

Age 14 to 16 Challenge Level:


The mean is a type of average of a set of numbers.
The mean is the total of the numbers divided by how many numbers there are. 

Try starting with a specific example.

Group A is composed of people aged 2, 7, 11, 14 and 16 (average 10)
Group B is composed of people aged 5, 11, 12, 13 and 19 (average 12)

Investigate what happens to the averages when different members move from one group to the other.