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Probability - April 20, 2004

The GMAT Sample Math question for the day is from the topic Probability.

Question
A man can hit a target once in 4 shots. If he fires 4 shots in succession, what is the probability that he will hit his target?

A. 1
B.
C.
D.
E.

The correct choice is (D) and the correct answer is .

Explanatory Answer
The man will hit the target even if he hits it once or twice or thrice or all four times in the four shots that he takes.

So, the only case where the man will not hit the target is when he fails to hit the target even in one of the four shots that he takes.

The probability that he will not hit the target in one shot = 1 - =
Therefore, the probability that he will not hit the target in all the four shots =

Hence, the probability that he will hit the target at least in one of the four shots = 1 -
= .
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