Advertisements
Advertisements
Question
What is the probability that the 13th days of a randomly chosen month is Friday?
Solution
Probability of any chosen month out of 12 months = \[\frac{1}{12}\]
There are seven possible ways in which a month can start and it will be a Friday on the 13th day if the first day of the month is Sunday.
So, its probability = \[\frac{1}{7}\]
Thus, required probability = \[\frac{1}{12} \times \frac{1}{7} = \frac{1}{84}\]
Hence, the probability that the 13th day of a randomly chosen month is Friday = \[\frac{1}{84}\]
APPEARS IN
RELATED QUESTIONS
2 boys and 2 girls are in Room X, and 1 boy and 3 girls in Room Y. Specify the sample space for the experiment in which a room is selected and then a person.
The numbers 1, 2, 3 and 4 are written separately on four slips of paper. The slips are put in a box and mixed thoroughly. A person draws two slips from the box, one after the other, without replacement. Describe the sample space for the experiment.
A die is thrown repeatedly until a six comes up. What is the sample space for this experiment?
If a coin is tossed two times, describe the sample space associated to this experiment.
If a coin is tossed three times (or three coins are tossed together), then describe the sample space for this experiment.
A coin is tossed and then a die is rolled only in case a head is shown on the coin. Describe the sample space for this experiment.
An experiment consists of tossing a coin and then tossing it second time if head occurs. If a tail occurs on the first toss, then a die is tossed once. Find the sample space.
A coin is tossed. If it shows tail, we draw a ball from a box which contains 2 red 3 black balls; if it shows head, we throw a die. Find the sample space of this experiment.
A coin is tossed repeatedly until a tail comes up for the first time. Write the sample space for this experiment.
A coin is tossed twice. If the second draw results in a head, a die is rolled. Write the sample space for this experiment.
In a random sampling three items are selected from a lot. Each item is tested and classified as defective (D) or non-defective (N). Write the sample space of this experiment.
An experiment consists of boy-girl composition of families with 2 children.
What is the sample space if we are interested in knowing whether it is a boy or girl in the order of their births?
2 boys and 2 girls are in room P and 1 boy 3 girls are in room Q. Write the sample space for the experiment in which a room is selected and then a person.
A box contains 1 white and 3 identical black balls. Two balls are drawn at random in succession without replacement. Write the sample space for this experiment.
A coin is tossed. Find the total number of elementary events and also the total number events associated with the random experiment.
List all events associated with the random experiment of tossing of two coins. How many of them are elementary events.
Three coins are tossed once. Describe the events associated with this random experiment:
A = Getting three heads
B = Getting two heads and one tail
C = Getting three tails
D = Getting a head on the first coin.
(iii) Which events are compound events?
A card is drawn at random from a pack of 52 cards. Find the probability that the card drawn is either a black card or a king
A card is drawn at random from a pack of 52 cards. Find the probability that the card drawn is neither a heart nor a king
A card is drawn at random from a pack of 52 cards. Find the probability that the card drawn is neither an ace nor a king
A card is drawn at random from a pack of 52 cards. Find the probability that the card drawn is not a diamond card
A card is drawn at random from a pack of 52 cards. Find the probability that the card drawn is a black card
A card is drawn at random from a pack of 52 cards. Find the probability that the card drawn is not an ace
A card is drawn at random from a pack of 52 cards. Find the probability that the card drawn is not a black card.
Tickets numbered from 1 to 20 are mixed up together and then a ticket is drawn at random. What is the probability that the ticket has a number which is a multiple of 3 or 7?
A bag contains 7 white, 5 black and 4 red balls. If two balls are drawn at random, find the probability that one ball is black and the other red
A committee of two persons is selected from two men and two women. What is the probability that the committee will have one man?
A class consists of 10 boys and 8 girls. Three students are selected at random. What is the probability that the selected group has at least one girl?
A bag contains tickets numbered from 1 to 20. Two tickets are drawn. Find the probability that on one there is a prime number and on the other there is a multiple of 4.as
An urn contains 7 white, 5 black and 3 red balls. Two balls are drawn at random. Find the probability that one ball is red and the other is black
An urn contains 7 white, 5 black and 3 red balls. Two balls are drawn at random. Find the probability that one ball is white.
An integer is chosen at random from first 200 positive integers. Find the probability that the integer is divisible by 6 or 8.
A sample space consists of 9 elementary events E1, E2, E3, ..., E9 whose probabilities are
P(E1) = P(E2) = 0.08, P(E3) = P(E4) = P(E5) = 0.1, P(E6) = P(E7) = 0.2, P(E8) = P(E9) = 0.07
Suppose A = {E1, E5, E8}, B = {E2, E5, E8, E9}
Using the addition law of probability, find P(A ∪ B).
A sample space consists of 9 elementary events E1, E2, E3, ..., E9 whose probabilities are
P(E1) = P(E2) = 0.08, P(E3) = P(E4) = P(E5) = 0.1, P(E6) = P(E7) = 0.2, P(E8) = P(E9) = 0.07
Suppose A = {E1, E5, E8}, B = {E2, E5, E8, E9}
List the composition of the event A ∪ B, and calculate P(A ∪ B) by addting the probabilities of elementary events.
A single letter is selected at random from the word 'PROBABILITY'. What is the probability that it is a vowel?
One card is drawn from a pack of 52 cards. The probability that it is the card of a king or spade is
A pack of cards contains 4 aces, 4 kings, 4 queens and 4 jacks. Two cards are drawn at random. The probability that at least one of them is an ace is
Three digit numbers are formed using the digits 0, 2, 4, 6, 8. A number is chosen at random out of these numbers. What is the probability that this number has the same digits?
A typical PIN (personal identification number) is a sequence of any four symbols chosen from the 26 letters in the alphabet and the ten digits. If all PINs are equally likely, what is the probability that a randomly chosen PIN contains a repeated symbol?
Three of the six vertices of a regular hexagon are chosen at random. What is the probability that the triangle with these vertices is equilateral?
