Pigeonhole (1 Viewer)

[moderntortoisecat]

Baruch has two spinners, each with three sides labelled with the numbers 1, 2, 3. He throws the pair of spinners and records their sum. What is the minimum number of throws of the pair required to ensure that the same total occurs at least twice?

Also, does any recommend some good resources for trying to understand the cambridge textbook questions? They take me out every time

 

[carrotsss]

How many totals can you make with the numbers on the spinners - ie how many pigeonholes are there?

 

[moderntortoisecat]

How many totals can you make with the numbers on the spinners - ie how many pigeonholes are there?

You can make 6 totals, so would that just be my answer?

 

[carrotsss]

You can make 6 totals, so would that just be my answer?

The possible totals with numbers 1-3 are 2, 3, 4, 5, 6, so there’s 5 of them, and so by pigeonhole principle if we want to ensure that one occurs at least twice we need 5+1=6 throws - if we just did the number of possible totals then it would be possible for one of each total to occur and then none would occur twice