View Full Version : probability
snydlite
Aug 2, 2012, 07:08 AM
How many ways are there to choose a patotoe and two green vegetables form a choice of three potatoes and seven green vegetables
Unknown008
Aug 2, 2012, 08:29 AM
What is your attempt?
snydlite
Aug 2, 2012, 08:32 AM
what is your attempt?
3*7*3
Unknown008
Aug 2, 2012, 08:33 AM
Why did you pick those numbers and multiply them this way?
Note that what you did is not fully right.
snydlite
Aug 2, 2012, 08:36 AM
Why did you pick those numbers and multiply them this way?
Note that what you did is not fully right.# of slots and items
Unknown008
Aug 2, 2012, 08:38 AM
That's not how you do it...
If I asked you to find the number of ways of picking 3 distinct tomatoes from a group of 10 tomatoes, how many ways are there to pick those 3 tomatoes?
snydlite
Aug 2, 2012, 08:40 AM
That's not how you do it...
If I asked you to find the number of ways of picking 3 distinct tomatoes from a group of 10 tomatoes, how many ways are there to pick those 3 tomatoes?
Idk
Unknown008
Aug 2, 2012, 08:44 AM
I asked you to pick 3 tomatoes.
You therefore have 3 slots.
_ _ _
In the first slot, you can have one of the 10 tomatoes, effectively giving you 10 ways of picking the first tomato.
10 _ _
In the second slot, you now have only 9 tomatoes to pick from. Therefore, you have 9 ways of picking the second tomato.
10 9 _
With the same logic, you are left with 8 ways.
10 9 8
Total number of ways = 10*9*8 = 720 ways.
Can you try your question now?
snydlite
Aug 2, 2012, 08:48 AM
I asked you to pick 3 tomatoes.
You therefore have 3 slots.
_ _ _
In the first slot, you can have one of the 10 tomatoes, effectively giving you 10 ways of picking the first tomato.
10 _ _
In the second slot, you now have only 9 tomatoes to pick from. Therefore, you have 9 ways of picking the second tomato.
10 9 _
With the same logic, you are left with 8 ways.
10 9 8
Total number of ways = 10*9*8 = 720 ways.
Can you try your question now?
Got it ty its 126
Unknown008
Aug 2, 2012, 08:49 AM
Yup, that's it :)