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## 'Put Out the Flags' printed from http://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.