Probability-Odds

Question

Plz explain

Bunuel · Answer

I think there should be "probability" instead of "odds".

We want light bulb NOT to bun out during the first 6 month and to burn out during the next 6 months period:

Probability of not burning out during the first 6 months  1-\frac{1}{3}=\frac{2}{3} ;

Probability of not burning out during the next 6 months  \frac{\frac{2}{3}}{2}=\frac{1}{3} , hence  probability of burning out  is  1-\frac{1}{3}=\frac{2}{3} .

Probability of burning out during the period from 6 months to 1 year = Probability of not burning out in first 6 months * Probability of burning out in next 6 months =  \frac{2}{3}* \frac{2}{3} =\frac{4}{9}

Answer: D.

vscid · Answer

Is this question asking to find odds or is it asking to find probability because they are not the same. I am confused.

IanStewart · Answer

Yes, I'm sure the question means to use the word *probability* every time it says 'odds'. Probability and odds are different things; any source that uses these words interchangeably is making a fundamental mathematical mistake. If you take the question literally, and assume they truly mean 'odds', the correct answer is 3/7, which is not among the answer choices; they clearly mean to use 'probability', in which case the answer is, as pointed out above, 4/9. Where is this question from?

Real GMAT questions always ask about probabilities and not about odds, and you do not need to know what 'odds' are for the test.

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Real GMAT questions always ask about probabilities and not about odds, and you do not need to know what 'odds' are for the test.

dixitraghav · Answer

For each 6-month period during a light bulb's life span, the odds of it not burning out from over-use are half what they were in the previous 6-month period. If the odds of a light bulb burning out during the first 6-month period following its purchase are , what are the odds of it burning out during the period from 6 months to 1 year following its purchase?

A. 5/27
B. 2/9
C. 1/3
D. 4/9
E. 2/3

A. 5/27 
 B. 2/9 
 C. 1/3 
 D. 4/9 
 E. 2/3

sag · Answer

I think there is something missing

If the odds of a light bulb burning out during the first 6-month period following its purchase are ____

Probability-Odds

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