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'Put Out the Flags' printed from https://nrich.maths.org/
Why do this
problem?
This problem
gives practice in calculating with percentages. It can be
approached by trial and improvement but the equivalence between
fractions and percentages is very useful.
Key questions
What fraction is $50$%? and $35$%?
What would be a sensible number to try first?
Do you think they will not have a whole number of flags?
Tim could have $100$ flags but could he have less than $100$
flags?
If $50$% of Tim's flags are blue, what does this tell you
about the number of flags Tim must have?
As $35$% of Tim'??s flags are red, what does
this tell you about the number of flags Tim must have?
Possible extension
Learners could devise and solve a second part to the question,
similar to that one in the problem.
Possible support
Suggest working with counters or drawing the flags starting with a
suitable arbitrary number and working by trial and improvement.