(March 21, 2020 at 4:03 pm)polymath257 Wrote: There are three types of people: those you can count, and those who can't.
Probabilities are all about counting.
(March 18, 2020 at 5:19 am)WinterHold Wrote: I have a probability question that I need to solve:
A set S is composed of 20 multi-colored objects. 4 objects were chosen randomly from S.
What is the probability that 3 of the chosen objects be blue; knowing that there are 8 blue objects in S ?
So, I don't need hell loads of math theory. I only want steps for a solution and I'll be thankful.
Please help me.
OK, steps for a solution:
1. Determine how many ways there are for picking out three blue objects.
2. Determine how many different ways there are to pick out four objects.
3. Divide the result from 1 by the result from 2.
I am wondering what exactly is being tested here. Basic probability or combinations and permutations at a level up from that? OP did not specify.
I framed my response on pragmatism. For such a small number of elements, it quicker to do some rough and ready quick calculations. For larger sets that would be utterly impractical.
If the OP was seeking to go down the nCk/nPk route, I might have framed it differently.
Still wouldn't have given a complete answer, though. It ain't our job to do his homework.
