#### 题目列表

Three coins-two 10-cent coins and one 5-cent coin--are to be flipped simultaneously. For each of the three coins, the probability that the coin will land heads up is $\frac{1}{2}$. What is the probability that the total value of the coins that will land heads up is 15 cents?
When selecting two numbers without replacement from 5, 8, 9, 9, 9, what is the probability that the sum of the two selected numbers is a multiple of 3?
p is the probability that event E will occur, and s is the probability that event E will not occur.

p+s

#### Quantity B

ps

Among Event A, Event B and Event C, Event B and Event C are mutually exclusive.

0 < P(A) < 1, P(A)=2P(B)=3P(C)

2/3 P(A)

#### Quantity B

P(B or C)

In box H, there are 5 red balls, 3 green balls and 2 yellow balls, while In box R, there are 3 red balls and 7 yellow balls. If someone selects one ball from each box, what is the probability that he or she selects at least one yellow ball?
What is the probability that the selected number are the same when selecting one letter from each of the word JOHNONS and JONES?
Set A: {71,73,79,83,87}
Set B: {57,59,61,67}
If one number is selected at random from set A, and one number is selected at random from set B, what is the probability that both numbers are prime?
20 boys and 40 girls are in Group A, while at least 7 boys, together with some girls are in Group B. To choose one person from each of the group, the probability that both are boys is no greater than $\frac{1}{15}$. Which of the following statements must be true?
Indicate all such statements.
A and B are independent events, and the probability that both events occur is $\frac{1}{2}$. Which of the following could be the probability that event A occurs?
Indicate all such probabilities.
Events A and B are independent. The probability that events A and B both occur is 0.6

#### Quantity A

The probability that event A occurs

#### Quantity B

0.3

A box contains 10 balls numbered from 1 to 10 inclusive. If Ann removes a ball at random and replaces it, and then Jane removes a ball at random, what is the probability that both women removed the same ball?
In a probability experiment, G and H are independent events. The probability that G will occur is r, and the probability that H will occur is s, where both r and s are greater than 0.

#### Quantity A

The probability that either G will occur or H will occur, but not both

#### Quantity B

r+s-r*s

A telephone system has n telephone lines. For each of the n lines, the event that the line will fail during a certain reliability test has probability 0.3, and these n events are independent. If the probability that at least one of the n lines will not fail during the reliability test is greater than 0.99, what is the minimum value of n?
There are only identical number of red and green balls in a box. A person first randomly selects a ball from the box without replacement, and continues to select another ball. Which of the following probability is 1/2?
Indicate all that are true.
The probability that a component fails during first use is 0.1. If the component doesnt fail during first use, then the probability that the component wont fail in the following six months is 0.8

#### Quantity A

The probability that the component wont fail within six months

#### Quantity B

0.75

Among 5 different red envelopes, 2 include cash, 3 include gifts. If you choose two red envelopes without replacement, what is the probability that cash is selected at least once?
In a box, the probability that the red ball is selected is $\frac{5}{8}$. Mark randomly selects balls twice from the box without replacement. If he didnt get a red ball in the first attempt, then the probability that he gets a red ball in the second attempt is $\frac{2}{3}$. What is the probability that Mark get at least one red ball?
In a box, the probability that the red ball is selected is $\frac{5}{8}$. Mark randomly selects balls twice from the box without replacement. If he didn`t get a red ball in the first attempt, then the probability that he gets a red ball in the second attempt is $\frac{2}{3}$. What is the probability that Mark gets one red ball either in the first attempt, or in the second attempt, but not both?
For a certain probability experiment, the probability that event A will occur is $\frac{1}{2}$ and the probability that event B will occur is $\frac{1}{3}$. Which of the following values could be the probability that the event A∪B (that is, the event A or B, or both) will occur?