You may also like

Bat Wings

Two students collected some data on the wingspan of bats, but each lost a measurement. Can you find the missing information?

Mediant Madness

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

Kate's Date

When Kate ate a giant date, the average weight of the dates decreased. What was the weight of the date that Kate ate?

Searching for Mean(ing)

Age 11 to 16
Challenge Level

Khue from British Vietnamese International School in Vietnam said:

An easier way of finding a mean weight for a combination of weights that is [the] numbers weights add up to a multiple of 5.

These diagrams illustrate Khue's reasoning:


In fact, there are combinations of 3 kg and 8 kg weights which have means equal to 3, 4, 5, 6, 7 and 8 kg. Click to see them all.

 mean = 3
 mean = 4
 mean = 5
 mean = 6
 mean = 7
 mean = 8


Mahdi from Mahatma Gandhi International School in India used algebra to extend the problem to other pairs of weights: