alleryWhat is the expected number of pips on one toss of a fair six-sided die?
- 4
- 3.5
- 2.5
- 3
Show answer and solution
Correct answer: B. 3.5
Each face has chance 1/6, so the mean is (1+2+3+4+5+6)/6 = 3.5.
GMAT Probability — practice questions — page 3
Explore 104 free Probability questions in GMAT Quantitative Aptitude. Open each question or exercise to read its content, reference answers and available explanation.
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Showing questions 61–90 of 104.
What is the expected number of pips on one toss of a fair six-sided die?Read the answer and worked solution →A game pays Rs 100 with probability 0.2 and nothing otherwise. What is the expected payoff?Read the answer and worked solution →You may gain Rs 40 or Rs 100 with equal chance. What is the value of this expectation?Read the answer and worked solution →Given P(B given A) = 0.8, P(A) = 0.3 and P(B) = 0.6, what is P(A given B)?Read the answer and worked solution →If P(A given B) = 0.5, P(B) = 0.2 and P(A) = 0.25, find P(B given A).Read the answer and worked solution →An event has probability 0.75. What are the odds in its favour?Read the answer and worked solution →The odds in favour of an event are 2 to 3. What is its probability?Read the answer and worked solution →Odds on rain are quoted as 1 to 4 in favour. What is the chance of rain?Read the answer and worked solution →An experiment has 12 equally likely outcomes, 3 of which are desired. What is the probability?Read the answer and worked solution →A bag has 5 red, 3 green and 2 blue balls. What is the chance of drawing a green ball?Read the answer and worked solution →Two balls are drawn without replacement from 2 red and 2 blue balls. Chance both are red?Read the answer and worked solution →A coin and a die are thrown together. What is the chance of heads and an even number?Read the answer and worked solution →Independent events each have probability 0.5. What is the chance at least one occurs?Read the answer and worked solution →A probability of 25 percent is written as which decimal?Read the answer and worked solution →Independent events have P(A) = 0.3 and P(B) = 0.5. What is P(B given A)?Read the answer and worked solution →Mutually exclusive events A and B have P(A) = 0.35 and P(A or B) = 0.8. Find P(B).Read the answer and worked solution →A draw pays Rs 1000 with chance 0.01 and Rs 100 with chance 0.05, else nothing. Expected payoff?Read the answer and worked solution →A die is rolled and Rs 30 is paid if the score is even, otherwise nothing. Expected payoff?Read the answer and worked solution →The probability of an event is a number lying between which two values?Read the answer and worked solution →In which year did Fermat and Pascal begin their famous correspondence on probability?Read the answer and worked solution →Christiaan Huygens gave the earliest known scientific treatment of probability in which year?Read the answer and worked solution →In which year did Andrey Markov introduce the notion of Markov chains?Read the answer and worked solution →Jakob Bernoulli's Ars Conjectandi appeared posthumously in which year?Read the answer and worked solution →The set of all possible results of an experiment is called its?Read the answer and worked solution →Which view treats probability as the relative frequency of an outcome over repeated trials?Read the answer and worked solution →Which interpretation of probability treats it as a degree of belief?Read the answer and worked solution →Bayes's essay on the doctrine of chances was published in which year?Read the answer and worked solution →In Bayes' rule, the posterior is proportional to the prior times which quantity?Read the answer and worked solution →Which result relates P(A given B) to its inverse P(B given A)?Read the answer and worked solution →The use of the letter E for expected value goes back to Whitworth in which year?Read the answer and worked solution →
Worked practice questions
A game pays Rs 100 with probability 0.2 and nothing otherwise. What is the expected payoff?
- Rs 80
- Rs 20
- Rs 10
- Rs 50
Show answer and solution
Correct answer: B. Rs 20
Multiplying the prize by its probability gives 100 x 0.2 = Rs 20.
You may gain Rs 40 or Rs 100 with equal chance. What is the value of this expectation?
- Rs 70
- Rs 60
- Rs 140
- Rs 100
Show answer and solution
Correct answer: A. Rs 70
With equal chances the expectation is the average of the two gains, (40 + 100)/2 = Rs 70.
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