Question

Consider the following sets of numbers.
A={all +ve even numbers less than 25}
B={all prime numbers less than 25}
Suppose a number is chosen at random from 1 to 25.

(a) Find P(A), P(B) and P(A∩B).
(b) Hence find (AUB).

@marigirl

Answer 1

@marigirl is it include 25?

Answer 2

no i will not include 25 .. anyway it wont matter
P(A)= total of 12 numbers. therefore if a random number is chosen from 1-25, what will be the probability it will be a even number
P(A)=12/25

Answer 3

do u have ans to check

Answer 4

P(A)=12/25

Answer 5

awesome. i checked out and found out there are 9 prime numbers for our given restiction. so what will P(B) be?

Answer 6

1 isn't prime number, is it?

Answer 7

no, 1 is not prime (plus i goggled it :P)

Answer 8

2, 3, 5, 7, 11, 13, 17, 19, 23

is 2 a prime number?

Answer 9

2, 3, 5, 7, 11, 13, 17, 19, 23
yes ur on track

Answer 10

9/25

Answer 11

yes

Answer 12

then P(A∩B)=1/25

Answer 13

2, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 16, 17, 18, 19, 20, 22, 23 ,24

Answer 14

sorry for the late reply

Answer 15

I agree with that:

then P(A∩B)=1/25

Answer 16

last one Hence find (AUB).

Answer 17

20/25=4/5

Answer 18

P(A U B) = P(A) + P(B)

Answer 19

and minus 1

Answer 20

but it means everything that is in either of the sets

Answer 21

but '2' is repeated

Answer 22

no ur right, sorry

Answer 23

thats why they wrote "Hence" find A U B

Answer 24

anyways i gotta go,
well done, you did most of the work!

Answer 25

thank you haha