[Blindmath] Amplification of Seemingly basic math question involving probability

Matthew_2010 Matthew_2010 at charter.net
Wed Sep 30 23:12:09 UTC 2009


Just thought I'd correct an error in my question below.

Alright all, I'm embarrassed to ask but here goes.

Yesterday one of my kids asked me to help with a math problem he couldn't 
work out and its been driving me a little crazy, so here I am. He was asked 
to determine the probability of flipping a coin and getting heads on first 
flip, heads on second flip, and tails on third flip. I'm thinking that 
because these are independent events its a matter of multiplying 1/2 * 1/2 * 
1/2. Therefore, the answer is that there is a 12.5% chance of flipping 3 
times and getting this pattern of flips.

The part of the problem that's bugging me is the tails part. Shouldn't this 
be a different probability since its the third flip and specified as tails? 
In other words, if the third flip was heads it wouldn't change the 
probability at all since they would all be equal (1/2). What role does a 
third tails flip play in the matter? (Hmm).

Matthew






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