事件概率-DS-OG：第1-4题 练习册详情

1

Terry holds 12 cards, each of which is red, white, green, or blue. if a person is to select a card randomly from the cards Terry is holding, is the probability less than 1/2 that the card selected will be either red or white?

(1) The probability that the person will select a blue card is 1/3.

(2) The probability that the person will select a red card is 1/6.

• Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
• Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
• BOTH statement TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
• EACH statement ALONE is sufficient.
• Statements (1) and (2) TOGETHER are NOT sufficient.

1562人做过此题 平均耗时为1min59s 平均正确率为 75%

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2

Each of the marbles in a jar is either red or white or blue. If one marble is to be selected at random from the jar, what is the probability that the marble will be blue?

(1) There are a total of 24 marbles in the jar, 8 of which are red.

(2) The probability that the marble selected will be white is $$\frac{1}{2}$$.

• Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
• Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
• BOTH statement TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
• EACH statement ALONE is sufficient.
• Statements (1) and (2) TOGETHER are NOT sufficient.

4122人做过此题 平均耗时为12min13s 平均正确率为 64%

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3

Jill has applied for a job with each of two different companies. What is the probability that she will get job offers from both companies?

(1) The probability that she will get a job offer from neither company is 0.3.

(2) The probability that she will get a job offer from exactly one of the two companies is 0.5.

• Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
• Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
• BOTH statement TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
• EACH statement ALONE is sufficient.
• Statements (1) and (2) TOGETHER are NOT sufficient.

73人做过此题 平均耗时为1min20s 平均正确率为 71%

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4

In a real estate office that employs n salespeople, f of them are females and x of the females are new employees. What is the value of n?

(1)If an employee were randomly selected from the n employees, the probability of selecting a female would be 2/3

(2)If an employee were randomly selected from the f female employees, the probability of selecting a new employee would be 1/2

• Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
• Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
• BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
• Each statement ALONE is sufficient.
• Statements (1) and (2) TOGETHER are NOT sufficient.

1063人做过此题 平均耗时为8min15s 平均正确率为 61%

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