Advertisements
Advertisements
प्रश्न
In Class XI of a school 40% of the students study Mathematics and 30% study Biology. 10% of the class study both Mathematics and Biology. If a student is selected at random from the class, find the probability that he will be studying Mathematics or Biology.
Advertisements
उत्तर
40% of the students in a school study Mathematics.
∴ Probability of a student studying Mathematics P(M) = `40/100 = 0.4`
30% of the students study Biology.
∴ Probability of a student studying Biology P(B) = `30/100 = 0.3`
∴ 10% of the students study both Mathematics and Biology.
∴ Probability of students taking Mathematics and Biology, P(M ∩ B)
= `10/100`
= 0.1
Now if a student is selected at random, then the probability of that student taking Mathematics or Biology is
P(M ∪ B) = P(M) + P(B) – P(M ∩ B)
= 0.4 + 0.3 – 0.1
= 0.6
APPEARS IN
संबंधित प्रश्न
If `2/11` is the probability of an event, what is the probability of the event ‘not A’.
A and B are events such that P(A) = 0.42, P(B) = 0.48 and P(A and B) = 0.16. Determine P(not A).
A and B are events such that P(A) = 0.42, P(B) = 0.48 and P(A and B) = 0.16. Determine P (not B)
In a class of 60 students, 30 opted for NCC, 32 opted for NSS and 24 opted for both NCC and NSS. If one of these students is selected at random, find the probability that
- The student opted for NCC or NSS.
- The student has opted neither NCC nor NSS.
- The student has opted NSS but not NCC.
A dice is thrown. Find the probability of getting a multiple of 2 or 3.
In a simultaneous throw of a pair of dice, find the probability of getting a doublet
In a simultaneous throw of a pair of dice, find the probability of getting a sum greater than 9
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 a total of 9 or 11
In a simultaneous throw of a pair of dice, find the probability of getting a total greater than 8.
In a single throw of three dice, find the probability of getting a total of 17 or 18.
Three coins are tossed together. Find the probability of getting at least two heads
Three coins are tossed together. Find the probability of getting at least one head and one tail.
Two dice are thrown. Find the odds in favour of getting the sum 5.
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 .
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) |
| 0.35 | .... | 0.25 | 0.6 |
In a single throw of two dice, find the probability that neither a doublet nor a total of 9 will appear.
Find the probability of getting 2 or 3 tails when a coin is tossed four times.
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 person write 4 letters and addresses 4 envelopes. If the letters are placed in the envelopes at random, then the probability that all letters are not placed in the right envelopes, is
Three integers are chosen at random from the first 20 integers. The probability that their product is even is
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
One mapping is selected at random from all mappings of the set A = {1, 2, 3, ..., n} into itself. The probability that the mapping selected is one to one 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.
