PROBABILITY
: Sum based on balls
Sol.
Q. A bag contains lemon flavoured candies only, Malini takes out one candy without looking into the bag. What is the probability that she takes out
(i) an orange flavoured candy?
(ii) a lemon flavoured candy?
Let the number of of lemon flavoured candies be x.
∴ Total number of possible outcomes = x
Let A be event that the candy taken out is orange flavoured candy
Numbers of outcomes favourable to A = 0
∴ P (A) =
x
Let B be the event that the candy taken out is lemon flavoured.
Numbers of outcomes favourable to B = x
∴ P (B) =
Does the bag contain any orange flavoured candy ?
NO
How many lemon flavoured candies are there ?
Sol.
Q. A bag contains 3 red balls and 5 black balls. A ball is drawn at random from the bag. What is the probability that the ball drawn is (i) red? (ii) not red?
A bag contains 3 red ball and 5 black balls.
Total no. of possible outcomes = 8
Let A be the event that the ball drawn is red.
No of outcomes favourable to A =
∴ P (A) =
Let B be the event that the ball drawn is not red.
No of outcomes favourable to B = 5
∴ P (B) =
How many red balls are there ?
There are two colour balls
If the ball drawn is not red then it will be which colour ball
How many black balls are there ?