Advertisements
Advertisements
प्रश्न
Three numbers are chosen from 1 to 20. The probability that they are not consecutive is
पर्याय
- \[\frac{186}{190}\]
- \[\frac{187}{190}\]
- \[\frac{188}{190}\]
- \[\frac{18}{^{20}{}{C}_3}\]
Advertisements
उत्तर
Number of ways to choose three numbers from 1 to 20 = \[^{20}{}{C}_3\] = 1140
Now, the set of three consecutive numbers from 1 to 20 are (1, 2, 3), (2, 3, 4), (3, 4, 5), ...., (18, 19, 20).
So, the number of ways to choose three numbers from 1 to 20 such that they are consecutive is 18.
P(three numbers choosen are consecutive) =\[\frac{\text{ Number of ways to choose three consecutive numbers from 1 to 20} }{\text{ Number of ways to choose three numbers from 1 to 20} } = \frac{18}{^{20}{}{C}_3} = \frac{18}{1140} = \frac{3}{190}\]
∴ P(three numbers choosen are not consecutive) = 1 − P(three numbers choosen are consecutive) = \[1 - \frac{3}{190} = \frac{187}{190}\]
APPEARS IN
संबंधित प्रश्न
If E and F are events such that P(E) = `1/4`, P(F) = `1/2` and P(E and F) = `1/8`, find
- P(E or F)
- P(not E and not F).
A and B are events such that P(A) = 0.42, P(B) = 0.48 and P(A and B) = 0.16. Determine P(A or B).
A die has two faces each with number ‘1’, three faces each with number ‘2’ and one face with number ‘3’. If die is rolled once, determine
- P(2)
- P(1 or 3)
- P(not 3)
In a certain lottery, 10,000 tickets are sold and ten equal prizes are awarded. What is the probability of not getting a prize if you buy one ticket.
Out of 100 students, two sections of 40 and 60 are formed. If you and your friend are among the 100 students, what is the probability that
- you both enter the same sections?
- you both enter the different sections?
A dice is thrown. Find the probability of getting:
2 or 4
In a simultaneous throw of a pair of dice, find the probability of getting a doublet of prime numbers
In a simultaneous throw of a pair of dice, find the probability of getting a doublet of odd numbers
In a simultaneous throw of a pair of dice, find the probability of getting neither 9 nor 11 as the sum of the numbers on the faces
In a simultaneous throw of a pair of dice, find the probability of getting a sum more than 7
In a simultaneous throw of a pair of dice, find the probability of getting neither a doublet nor a total of 10
In a simultaneous throw of a pair of dice, find the probability of getting odd number on the first and 6 on the second
In a simultaneous throw of a pair of dice, find the probability of getting a total greater than 8.
Two dice are thrown. Find the odds in favour of getting the sum 4.
Two dice are thrown. Find the odds in favour of getting the sum 5.
Two dice are thrown. Find the odds in favour of getting the sum What are the odds against getting the sum 6?
A box contains 10 red marbles, 20 blue marbles and 30 green marbles. 5 marbles are drawn at random. From the box, what is the probability that all are blue?
A box contains 6 red marbles numbered 1 through 6 and 4 white marbles numbered from 12 through 15. Find the probability that a marble drawn is white .
A box contains 6 red marbles numbered 1 through 6 and 4 white marbles numbered from 12 through 15. Find the probability that a marble drawn is white and odd numbered .
A box contains 6 red marbles numbered 1 through 6 and 4 white marbles numbered from 12 through 15. Find the probability that a marble drawn is even numbered
A box contains 6 red marbles numbered 1 through 6 and 4 white marbles numbered from 12 through 15. Find the probability that a marble drawn is red or even numbered.
Fill in the blank in the table:
| P (A) | P (B) | P (A ∩ B) | P(A∪ B) |
| \[\frac{1}{3}\] | \[\frac{1}{5}\] | \[\frac{1}{15}\] | ...... |
Fill in the blank in the table:
| P (A) | P (B) | P (A ∩ B) | P(A∪ B) |
| 0.5 | 0.35 | ..... | 0.7 |
If A and B are two events associated with a random experiment such that
P(A) = 0.5, P(B) = 0.3 and P (A ∩ B) = 0.2, find P (A ∪ B).
If A and B are two events associated with a random experiment such that
P (A ∪ B) = 0.8, P (A ∩ B) = 0.3 and P \[(\bar{A} )\]= 0.5, find P(B).
There are three events A, B, C one of which must and only one can happen, the odds are 8 to 3 against A, 5 to 2 against B, find the odds against C
One of the two events must happen. Given that the chance of one is two-third of the other, find the odds in favour of the other.
A card is drawn at random from a well-shuffled deck of 52 cards. Find the probability of its being a spade or a king.
One of the two events must occur. If the chance of one is 2/3 of the other, then odds in favour of the other are
A bag contains 5 black balls, 4 white balls and 3 red balls. If a ball is selected randomwise, the probability that it is black or red ball is
An urn contains 9 balls two of which are red, three blue and four black. Three balls are drawn at random. The probability that they are of the same colour is
A box contains 10 good articles and 6 with defects. One item is drawn at random. The probability that it is either good or has a defect is
In a certain lottery 10,000 tickets are sold and ten equal prizes are awarded. What is the probability of not getting a prize if you buy two tickets.
In a certain lottery 10,000 tickets are sold and ten equal prizes are awarded. What is the probability of not getting a prize if you buy 10 tickets.
