Free Practice Question
PS · Problem Solving
555-605
Probability
In a box, there are 4 black balls and 6 white balls. If two balls are selected at random, what is the probability that at least one of them is black?
Answer Choices
Correct answer marked belowA
1/15
B
8/30
2/3
Correct
D
9/15
E
26/30
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Explanation
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Official Explanation
Official
In this scenario, we have 4 black balls and 6 white balls in the box. To find the probability of selecting at least one black ball, we can use the complement method. This means we will calculate the probability of not selecting any black balls and subtract that from 1. The event of not selecting at least one black ball corresponds to selecting zero black balls. Therefore, we can express…
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Comments
2
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A
ApuFeb 25, 2025
Thankss
B
BituDec 8, 2024
greatt question!
What this question tests
What it tests
Your ability to compute probabilities of single and compound events, including 'at least one' questions.
Common trap
Forgetting to use the complement for 'at least one', or treating dependent events as independent.
Details
Difficulty
555-605
Type
PS
Category