Today I am going to share Probability shortcuts for problems based on Dice. Must Probability trick: When 2 Dices rolled together.
If 1 appears
on the first dice, 1 on the second dice and 1 on the third dice.
The minimum sum with three dices rolled
together = 3
If 6 appears
on the first dice, 6 on the second dice and 6 on the third dice.
(6, 6, 6) = 6+6+6 =18
The maximum sum with three dices rolled
together = 18
The sum
could be 3, 4, 5, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, and 18.
- What is the probability of getting a sum of 4 if three dices are rolled together.
Solution:
Required probability = favorable case / total outcomes
= 3/216
= 1/72
- What is the probability of getting a sum of 5 if you throw three dices together?
Solution:
Now as you
can see that it is a time consuming method, let us find a quick method to find
the probability.
There are total
16 numbers (possible number of sums) and half of 16 is 8.
Counting 8
from both the sides we get 10 and 11 in the middle.
Now we will
construct the triangle which would help us to find the probability if three
dices are rolled together.
Memorizing the making of
the above picture makes the
calculation easier and faster.
- What is the probability of getting a sum of 11 if three dices are rolled together?
Solution:
From the table
Sum 11 = probability 27
Required probability = 27/216 =1/8
- What is the probability of getting a sum of 14 if three dices are rolled together?
Solution:
From the
table
Sum 14
= probability 15
Required
probability = 15/216
- What is the probability of getting a sum of 11 or 9 if three dices are rolled together?
Solution:
From the table
Sum 11 = probability 27
and sum 9 = probability 25
Since there is an ‘and’ so we will add
Required Probability =
27/216 +25/216 = 52/216
- If 3 dices are rolled at the same time. What is the probability of all 3 dice showing even face values?
Solution: Even faces
means 2, 4, 6
There are 3
ways 2 can appear on in first go.
Similarly, there are 3 ways 4 can appear on in first go.
.
There are 3
ways 6 can appear on in first go.
So total number of ways: 3+3+3
Required probability =
9/216 =1/24
- What is the probability of not getting 6 when 3 dice are rolled together?
Solution:
Probability of not getting 6 on the first die = 5/6
(As probability of getting 6 on first die is 1 so the probability
of not getting 6 = 6-1=5)
And
Similarly, Probability of not getting 6 on the second die = 5/6
And
Probability of not getting 6 on the third die = 5/6
So the required
probability = 5x5x5/216=125/216
Remember AND means multiply
and OR means ADD.

What's trending in BankExamsToday
Smart Prep Kit for Banking Exams by Ramandeep Singh - Download here
Join 40,000+ readers and get free notes in your email

wow......awesome trick sir hats off to you...................
ReplyDeletesir you gave similar shortcut lesson for probability but i lost that if available please send me the link sir
ReplyDeletesir there are no 2015 vacancies when i click on apply link there is just 2014 and old vacancies
ReplyDeleteThanks sir
ReplyDeleteSir please provide me notes for alligation mixture
ReplyDeleteraman sir please help me
ReplyDeletejust now i have filled ibps po5 application nd by mistake i selected muslim option(im hindu) as my religion .will it be a problem now ,i alredy paid fee what can i do now
14th ka ans 1881 hoga na??
ReplyDeleteIf 3 dices are rolled at the same time.
ReplyDeleteWhat is the probability of all 3 dice showing even face values? - Sir, shouldn't the number of favourable cases be 3*3*3=27?
Hi friends anybody from Coimbatore tomorrow attend SBI po exam
ReplyDeleteI am btech in civil engg...is this create any problem at the time of interview of bank po or bank clerk?
ReplyDeleteSir I m facing difficulty in probability on cards questions.. Can u plzz help in this matter?
ReplyDeleteAisa hai kya
ReplyDeleteya aisa hi hai
ReplyDeleteyup
ReplyDelete14 ans is 2
ReplyDelete