Probability is one of the most interesting topics in the IBPS RRB syllabus. This is not because of the nature of the questions but also because of the very fact, that a lot of candidates don’t get the answers right. What this means is that if you can master probability, you can expect to get the edge over the rest of the candidates and get successful in IBPS RRB 2021. So, how you can master probability? Well, you need three things – clear concepts, the right technique and a good deal of practice. Let’s take a look at how you can improve on each of them and solve IBPS RRB probability questions with ease.
Analysis of IBPS RRB Questions
Let us first understand the very nature of probability questions in RRB exam. There are a few things that you should know about this particular subject. So, let’s dive straight into it.
How Many Questions Come on Probability?
One of the first questions that a lot of people ask is how many questions come every year. Well, if you look at the previous year questions and make an average, you would find that roughly 3 to 4 questions come from probability. However, this doesn’t mean that you would get 3 or 4 probability questions. You can get more and you can get less as well.
How tough are they?
Probably questions are inherently complicated and hence, a bit tough to solve. The level of questions in IBPS RRB is more on the moderate side. The difficulty of the questions in the previous years has remained easy to moderate.
What are the Main Types of Questions?
There are a lot of different variants of IBPS RRB probability questions. Sometimes, there are questions on dices and coins. There are also questions about events and possibilities. So, when you are looking to prepare for IBPS PO and Office Assistants exam, you should focus on these main types of questions.
How Much Do I need to Practice?
Probability questions are pretty easy to solve once you know the right technique. Mastering the technique might take some time and practice. So, if you are new to probability, then you need to start practicing at least 5 to 6 months before the exam. Put in at least half an hour every alternate day for probability during this time and you would be fit for the exam.
Useful tricks for solving IBPS RRB Probability Questions
Let us look at some of the concepts and tricks that you should know about to get the help that you need to solve the toughest probability questions in IBPS RRB with a great deal of ease.
- Make the possible outcomes as the denominator and the desired outcome as the numerator. You can then use this fraction to find the percentage probability.
Let us take the example of dice. Let us say you are asked to get a two in a single throw on a single dice. What is the number of outcomes you can get on a single throw on a dice? Six, right? So, we keep 1 as our numerator and 6 as the denominator. So, the fraction that we are going to use is 1/6. Now, the probability percentage is (1/6)*100=16.67%.
- If you are given two dices or coins or anything else, and you are asked to deduce the possibility, you just need to multiply the fractions. For example, if there are two dices and you are asked to detect the possibility of getting a two when both the dices are thrown together, then the probability is 1/6 (for the first dice) multiplied by 1/6 (for the second dice). So, the total probability is 1/36.
Solving IBPS RRB Probability Questions
Let us look at an example and see how we can use the tricks learned above to solve the question.
Question: What is the probability of getting a prime number when two dices are thrown together?
Solution: Let us first work out the denominator of the fraction. The number of possible outcomes is 6 or one dice so for two dices, the number of possible outcomes is 6×6 =36. So, our denominator is 36.
Now, let’s look at the numerator. What are the prime numbers in a dice? 2,3 and 5, right? So, the number of desired outcomes is 3 for one dice. For two dices, it would be 3×3=9. Now, you need to understand that this is only for the possibility that one of the dice would have a prime number. Now, there is also a possibility that we would get prime number on both the dices. To include that, we just need to multiply 9 by 2, since we are throwing 2 dices. So, our numerator finally becomes 9×2=18.
So, the fraction is 18/36=1/2 or 50%
Question 1: What is the probability of getting sum 9 by rolling two dices at once?
Question 2: What is the possibility of getting an even number if one dice is thrown together?
Question 3: If 3 coins are thrown together, what is the possibility of getting at least one heads?
So, these were some of the things that you can try out to solve IBPS RRB probability questions. For more such useful articles, keep browsing our website.