Why do this
problem?
This problem is one which could be done quickly as an
introduction when extending or revising work on time and
clocks.
Key questions
When does the first bottle fall?
So when does the second bottle fall?
How many $5$ minutes are there between the first and tenth
bottles falling?
Possible extension
Learners could find the equation for the $nth$ bottle
falling.
Possible support
Suggest using a real or model clock and counting.