The test

The test contains four questions, and there are five different answers to each of them, of which only one is correct, the others are incorrect. What is the probability that a student who does not know the answer to any question will guess the right answers to all the questions?

Correct answer:

p =  0.16 %

Step-by-step explanation:

$$\begin{gathered} q=1\mathrm{/}5={\displaystyle \frac{1}{5}}=0.2 \\ n=4 \\ p=100\cdot q^n=100\cdot 0.2^4={\displaystyle \frac{4}{25}}={\displaystyle \frac{4}{25}}\mathrm{\%}=0.16\mathrm{\%} \end{gathered}$$

Try another example

Showing 1 comment:

Math student

You make it simple where I can understand thank you so much

11 months ago  Like

Related math problems and questions:

• Test
  The teacher prepared a test with ten questions. The student can choose one correct answer from the four (A, B, C, D). The student did not get a written exam at all. What is the probability that: a) He answers half correctly. b) He answers all correctly. c
• Six questions test
  There are six questions in the test. There are 3 answers to each - only one is correct. In order for a student to take the exam, at least four questions must be answered correctly. Alan didn't learn at all, so he circled the answers only by guessing. What
• Quiz or test
  I have a quiz with 20 questions. Each question has 4 multiple choice answers, A, B, C, D. THERE IS NO WAY TO KNOW THE CORRECT ANSWER OF ANY GIVEN QUESTION, but the answers are static, in that if the "correct" answer to #1 = C, then it will always be equal
• Boys and girls
  There are 11 boys and 18 girls in the classroom. Three pupils will answer. What is the probability that two boys will be among them?
• Intelligence test
  Paľo, Jano, Karol, and Rišo were doing an intelligence test. Palo correctly answered half of the questions plus 7 questions, Jano to a third plus 18 questions, Karol to a quarter plus 21 questions and Risho to a fifth plus 25 questions. After the test, Ka
• Answers
  After the history test, Michaella discovered that the ratio of her correct and incorrect answers is 5: 3. How many correct answers did Michaella have in the test, if she had 6 incorrect answers?
• A student
  A student is to answer 8 out of 10 questions on the exam. a) find the number n of ways the student can choose 8 out of 10 questions b) find n if the student must answer the first three questions c) How many if he must answer at least 4 of the first 5 ques
• Dice
  We throw five times the dice. What is the probability that six fits exactly twice?
• Math test
  Obelix filled a mathematical test in which he answered 25 questions. For every correct answer, he received 5 points, for each bad answer he had 3 points deducted. Obelix gained 36% of all points in the test. How many questions did he solve correctly?
• Dice
  We throw 10 times a playing dice. What is the probability that the six will fall exactly 4 times?
• Left handed
  It is known that 25% of the population is left-handed. What is the probability that there is a maximum of three left-handers at a seminar where there are 30 participants?
• Doctors
  The drug successfully treats 90% of cases. Calculate the probability that he will cure at least 18 patients out of 20?
• Families 2
  Seven hundred twenty-nine families are having six children each. The probability of a girl is 1/3, and the probability of a boy is 2/3. Find the number of families having two girls and four boys.
• Hazard game
  In the Sportka hazard game, 6 numbers out of 49 are drawn. What is the probability that we will win: a) second prize (we guess 5 numbers correctly) b) the third prize (we guess 4 numbers correctly)?
• TV fail
  The TV has after 10,000 hours average 35 failures. Determine the probability of TV failure after 400 hours of operation.
• Bernoulli distribution
  The production of solar cells produces 2% of defective cells. Assume the cells are independent and that a lot contains 800 cells. Approximate the probability that less than 20 cells are defective. (Answer to the nearest 3 decimals).
• Family
  94 boys are born per 100 girls. Determine the probability that there are two boys in a randomly selected family with three children.