Probability Tricks To Solve IBPS Quant Questions

Candidates consider Quantitative Aptitude as one of the dreaded and Ineluctable subjects for any banking and other competitive exams. This sections if practiced well can do wonders or may shock you anytime by raising the level of its complexity. You can also check out the Quantitative Aptitude Quiz.

We have already provided you with the study plan for IBPS PO in the form of KAR IBPS PO FATEH! and providing the daily quiz of the quant section based on various topics on the basis of the Study plan. Now we have also started a new initiative of making learning easy by providing study notes. Today we are discussing the Probability for Bank PO and other exams.

Probability means the chances of happening or occurring of an event

Event:-

              Event is the single result of an experiment

Ex. Getting a head is an event related to tossing of a coin

Types of event:-

                           Various types of events are as follow:

1. Certain event : It is a event which is certain to occur

2. Impossible event : It has no chance of occurring

Ex. A professor chooses a student at random from a class of 20 boys. What is the probability that the student chosen is boy?

Favourable cases = 20

total cases = 20

∴ Probability =20/20  = 1

3. Dependent events:- 

                                   Two events are called dependent if outcome or occurrence of the 1st affects the outcome or occurrence of the 2nd, so that probability is changed.

Ex. A card is chosen at random from a deck of 52 playing cards. without replacing it, a 2nd card is chosen. What is probability that 1st card chosen is king and the 2nd chosen is jack?

                                    Two events A and B are called independents if occurring or non-occurring of A does not affect the occurring or non-occurring of B.

Ex. A coin is tossed and a 6 sided dice is rolled find probability of getting a tail of coin and getting ‘2’ on dice?

Probability (Tail) =1/2

Probability of getting ‘2’ of dice =1/6

Some rule of Probability

1. Addition rule

P (A or B) = P(A) + P(B)

and P(A ∪ B) = P(A) + P(B)

2. Multiplication rule 

if A and B are independent event

P(A ∩ B) = P(A). P(B)

Ex. From a pack of 52 cards, a card is chosen at random, find the probability that it is either a king or a jack?

⇒ Different types of question asked on probability:-

1. Based on coins :-

                            In these type, questions are based on tossing of coins and obtaining a particular face (Head/Tail) or obtaining same face on two or more coins.

Ex.  A coin is tossed twice, then find probability that a tail is obtained atleast once?

When coin is tossed twice, total possible outcome = 4

Ways in which tail is obtained = 3

∴ Required probability =3/4

2. Based on Dice:-

                          These type of question is based on rolling of one or more dice and getting a particular number on the face or a sum of faces of dice.

Ex. A single dice is a rolled what is the probability of getting a 2 or 6?

3. Based on balls :-

                                 These types of questions are based on choosing a ball  of a particular colour from one or more bag containing different coloured balls.

Ex. In a bag, there are 3 white, 4 red and 5 Green balls. if two ball are chosen, find the probability of both balls being red ?

Here White balls= 3

Red balls = 4

Green balls = 5

If you want to study Quantitative Aptitude for IBPS PO Prelims then you can also check out the video given below:

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