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### Number and algebra

### Geometry and measure

### Probability and statistics

### Working mathematically

### Advanced mathematics

### For younger learners

# In the Bag

**150 points** for a perfect match

**100 points** for 9 matching marbles

**0 points** for 8 matching marbles

**-150 points** for 7 or fewer matching marbles.
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Age 11 to 14

Challenge Level

Ten marbles of varying colours are chosen at random and placed in a bag.

**Can you guess the colours of the 10 marbles in the bag?**

To help you make accurate predictions you can choose to see the results of 10 viewings - each viewing removes a marble out of the bag, records its colour and **returns it to the bag before repeating the process.**

You can choose to perform as many 10 random viewings as you like before deciding to "Guess".

Each Round concludes when you have made a guess.

**Can you reach a score of 1000 points?**

You start with 500 points. Each run of 10 viewings "costs" you 10 points but you can "earn" points by predicting accurately the contents of the bag:

Can you develop an effective strategy for reaching 1000 points?

Can you develop an effective strategy for reaching 1000 points in the least number of rounds?

Describe your strategies.

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