A card is drawn from a pack of cards.What is the probability that it is a card of black suit?
There are 26 cards of black suits
Total=52
No of events=26
Probability=26/52=1/2
A box contains 4 red balls,5 green balls and 6 white balls.A ball is drawn at random.Find the probability that the ball drawn is either red or green?
Total=15C1=15
No of events=4C1+5C1=9
Probability=9/15=3/5
An unbiased die is thrown.Find the probability of getting a multiple of 3
Total=6 {1,2,3,4,5,6}
Multiple of 3={3,6}, ie 2 events
Probability=2/6=1/3
In a throw of a coin,find the probability of getting a head.
Total=2 {H,T}
Probability of getting a head=1/2 {only one head}
A bag contains 7 white and 9 black balls.Two balls are drawn in succession at random.What is the probability that one of them is white and the other black?
Total probability=16C2=120
No of ways of drawing a white ball=7C1=7
No of ways of drawing a black ball=9C1=9
No of ways of drawing a white ball and a black ball=7*9=63
Probability=63/120=21/40
A bag contains 2 red,3 green and 2 blue balls,two balls are drawn at random.What is the probability that none of the drawn balls are blue?
Total=7C2=21
No of desired events=(2+3)=5C2=10
Probability=10/21
A bag contains 6 white and 4 red balls.Three balls are drawn at random.What is the probability that one ball is red and other two are white?
Total=10C3=120
No of desired events=60
Probability=60/120=1/2
A box contain 4 black balls,3 red balls and 5 green balls.2 balls are drawn from the box at random.Find the probability that balls are of the same color?
Total=12C2=66
No of desired events=4C2+3C2+5C2=6+3+10=19
Probability=19/66
A bag contains 6 black and 8 white balls.One ball is drawn at random.What is the probability that ball drawn iswhite?
Total probability=14C1=14
Probability of drawing a white ball=8/14=4/7
A bag contains 3 red,5 yellow and 4 green balls.Three balls are drawn randomly.What is theprobability that balls drawn contain exactly 2 green balls?
Total probability=12C3=220
Exactly 2 green balls can be selected from 4 green balls in 4C2 ways and rest one ball can be
selected from the remaining in 12-4=8 ways
4C2*8=48
Probability=48/220=12/55
A bag contains 6 white and 4 black balls.Two balls are drawn at random.Find the probability that they are of same
color?
Total Probability=10C2=45
Probability of having same color=(6C2+4C2)/10C2=21/45=7/15