Some problems are easy, some are very hard, but each is interesting in some way. Edit: For an alternative solution, check comment from Bhavya Shah. 36, 3x3 squares Sample Probability questions with solutions. Additionally, a third event occurs when the weatherman predicts rain. The possible split ups as far as colour is concerned and the number of ways of selecting the square are listed below: White = 0, Black = 4, No. The questions here will be provided, as per NCERT guidelines. 2020| If …, There are 20 frogs in the vertex's of a dodecahedron (one frog in one vertex) for the first time. 99977--->number of 5 digit =10 In a game there are 70 people in which 40 are boys and 30 are girls, out of which 10 people are selected at random. We need to find P(A or B). What is the probability of the occurrence of a number that is odd or less than 5 when a fair die is rolled. Sample space will be total ways of selecting 2 squares (order doesn't matter) out of available 64 squares. 4, 7x7 squares Why are the possibilities of rolling the dice for each number, this way : Below is the probability of rolling a certain number with two dice. 98888--->number of 5 digit =5, Now for a 5 digit number of form (pqrst) to be divisible by, $11(p+r+t)−(q+s)=11$, also $(p+r+t)+(q+s)=41$, $(p,r,t)=(9,9,8)$ and $(q,s)=(8,7)$ --------(i), or $(p,r,t)=(9,9,8)$ and $(q,s)=(9,6)$  --------(ii), Hence, required probability = 12/70 = 6/35. Forgot password? By being on this site, you allow cookies to be used. Find the probability that such a number is divisible by 11? 64, 1x1 squares. Probability Level 5 A toad is placed in a 5x5 square. Frequently asked simple and hard probability problems or questions with solutions on cards, dice, bags and balls with replacement covered for all competitive exams,bank,interviews and entrance tests. 1, 8x8 square You found a box with 1 trillion (101210^{12} 1012) coins inside. Almost all problems I have heard from other people or found elsewhere. It does not rain on Marie's wedding. B At first glance; we can think that a child can be either a girl or a boy, so the probability for the other child to be a girl is 1/2. The total number of ways of selecting 4 squares is: \(=\dfrac{64\times 63\times62\times61}{2\times3\times4}\). The Corbettmaths Practice Questions on Probability. pick it up. Terms of Service & Privacy Policy | All Rights Reserved, Contact us: Good quality fully solved "Probability" Problems as a part of Aptitude Test Question Answers have been given on this page. Log in. It is necessary to learn the basics of this concept. ], \(P(B|A_1)=0.9\) [When it rains, the weatherman predicts rain $90\%$ of the time. The sample space is defined by two mutually-exclusive events - it rains or it does not rain. Two squares are chosen at random on a chessboard. 8. The number of ways of choosing 4 squares from 64 is \(^{64}C_4\). Difficult Probability Question - 9. So the possibility of selecting 2 squares with a common side (As calculated in the first method above): having the side length greater than 4 unit length = 0 16, 5x5 squares 17 Responses to GMAT Probability: Difficult Dice Questions. Probability questions for S&T interview (Originally Posted: 04/01/2008) ... it was just expectation however it was near impossible to structure the answer. 99986--->number of 5 digit =20 9, 6x6 squares Now if we assume that 2 squares can have a side common only if they are of the same dimensions: What is the probability that they have a side in common? One from the total group, thus selected is selected as a leader at random. The possible sums for two dices are {2,3,4,5,6,7,8,9,10,11,12}\{2,3,4,5,6,7,8,9,10,11,12\}{2,3,4,5,6,7,8,9,10,11,12} Copyright ], \(P(A_2)=\dfrac{360}{365}=0.9863013\) [It does not rain 360 days out of the year. Online Practice of these difficult problems on Probability will enable you to perform well in Aptitude Tests of various competitive examinations like CAT, XAT, MAT, GRE, GMAT, SAT, IRMA, FMS, IIFT, NMIMS etc. the square within 1 square from current square)all … Sun Life Insurance company issues standard, preferred and ultra-preferred policies. The higher the probability of an event, the more likely it is to occur, i. E. Tossing a coin gives a 50% chance of getting heads or tails. The total groups contains boys and girls in the ratio $4:3$, If some person are selected at random from the group, the expected value of the ratio of boys and girls will be $4:3$, If the leader is chosen at random from the selection, the probability of him being a boy = 4/7. For a sequence of positive integers a1,a2,…,aka_{1},a_{2},\ldots,a_{k}a1​,a2​,…,ak​ , its value VVV …, If you take one coin from the box there is a 50% chance it’s a gold …. having the side length of 1 unit = 7×(8 rows + 8 columns) = 112. Edit 2: For yet another alternative solution, check comment by RandomMathMan. Let the event of the occurrence of a number that is odd be ‘A’ and the event of the occurrence of a number that is less than 5 be ‘B’. of Ways = ${^{32}C_2} × {^{32}C_2}$, White = 3, Black = 1, No. 49, 2x2 squares Edit 3: Here is yet another alternative solution from B Gogoi. The number of ways in which 3 squares are of one colour and fourth is of opposite colour is: $P(A) =2\times {^{32}C_1} \times {^{32}C_3}$, \(=(2\times 32)\dfrac{32\times 31\times 30}{2\times 3}\). The questions here will cover the basics as well as the hard level problems for all levels of students. ], \(P(B|A_2)=0.1\) [When it does not rain, the weatherman predicts rain $10\%$ of the time.]. In order to get the sum as 41, the following 5 digit combination exist: 99995--->number of 5 digits =5 (i.e. The dice is rolled and Bob writes down a number in his notebook, if it has not already been written down. of Ways = ${^{32}C_0} × {^{32}C_4}$, White = 1, Black = 3, No. Consider making a small contribution. total number of squares on a chess board. Event $A_2$. Four unit squares are chosen at random on a chessboard. When it actually rains, the weatherman correctly forecasts rain $90%$ of the time. Unfortunately, the weatherman has predicted rain for tomorrow. Q9. i.e. Edit: For an alternative solution, check comment by Laurence. if we consider that total squares are more than 64). In terms of probabilities, we know the following: \(P(A_1)=\dfrac{5}{365}=0.0136985\) [It rains 5 days out of the year. Also, there could be other solution too if we consider ALL possible squares and not only the smallest squares. Note the somewhat unintuitive result. In recent years, it has rained only 5 days each year. Sum of digits of a 5 digit number is 41. Richard Durret has a text called Probability: theory and example that is amazing. Let the length of the smallest square be 1 unit. Despite the weatherman's gloomy prediction, there is a good chance that Marie will not get rained on at her wedding. of Ways = ${^{32}C_4} × {^{32}C_0}$. Learn and practice basic word and conditional probability aptitude questions with shortcuts, useful tips to … Notation for these events appears below. Help us keep afloat. Even when the weatherman predicts rain, it only rains only about $11\%$ of the time. To appreciate the effort Lofoya.com is putting, Please like our page and help us spread the word. favourable cases will be 7×(8 rows + 8 columns) = 112. What is the probability that three of them are of one colour and fourth is of opposite colour? 99887--->number of 5 digit =30 Now there are 7 unique adjacent square sets in each row and each column. In that case, let us first calculate the sample space i.e. probability problems, probability, probability examples, how to solve probability word problems, probability based on area, examples with step by step solutions and answers, How to use permutations and combinations to solve probability problems, How to find the probability of of simple events, multiple independent events, a union of two events