I guess my first fascination with problems of Time, Speed and Distance began when I first saw Henna. An important part of the story line  if you can call it that, saw Rishi Kapoor floating from India to Pakistan without drowning. I remember arguing with my friends that if could float for that long – he could swim back to India as well. My friends nullified the argument by saying: Speed River > Speed Rishi Kapoor I know that the reference is a little dated for most readers of this post, but Zeba Bhaktiyar made me look beyond reason. In this post we will discuss some of the ideas that

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Figuring out the last digit is the same as figuring out the remainder of a number when divided by 10, but I guess you already know that. Figuring out the last two digits is the same as figuring out the remainder of a number when divided by 100. However, if you wish to figure the remainder when the divisor is not 10 or 100, I suggest you read on. Funda 1 of Remainders:  Basic idea of remainders can be used to solve complicated problems.     There is nothing special or unique about this idea. At first glance it seems like something really obvious. But it is it

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The concepts of Set Theory are applicable not only in Quant / DI / LR but they can be used to solve syllogism questions as well. Let us first understand the basics of the Venn Diagram before we move on to the concept of maximum and minimum. A large number of students get confused in this so I have listed out each area separately. A venn diagram is used to visually represent the relationship between various sets. What do each of the areas in the figure represent? I – only A; II – A and B but not C; III – Only B; IV – A and C but not B; V – A and B and

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Quadratic Equations are first taught to us in 6th or 7th class and most of us are able to score good marks in it because we are able to solve 90% of the questions by just using that formula. And that formula is: The above formula gives us the roots of the quadratic equation ax2 + bx + c = 0 For this post, I am assuming that you are aware of the basics of quadratic equations and know how to use the above mentioned formula. In case you are not, spending five minutes on the wiki page of Quadratic Equations won’t hurt. Wikipedia can be daunting at times, so come back here as soon a

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In this Number of trailing Zeros blog post, We would like to cover these two ideas: Number of trailing zeroes in a Product or Expression Number of trailing zeroes in a factorial (n!) But before I begin, let us first try to understand what exactly are ‘trailing zeroes’. It is nothing else but the number of zeroes at the end. I do not want to sound pedantic but on many occasions when you see a question which asks about, “What is the number of zeroes in ___” it is incorrect, because it should actually say – “What is the number of trailing zeroes?” or “What is the

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Understanding Percentage The word “Percent” can be understood as “per 100” or “out of 100”. Percentage in itself is a dimensionless number used to tell how many parts per hundred are being considered. It is often denoted using the percent sign, "%". The reference point for calculating percentage is taken as 100. If in a class of 100 students, 90 students passed in a subject then the percentage of students who passed in the exam is 90%. Had the total number of students been 200, the percentage would have reduced to 45%. This is because 45 students out of every 100 students pas

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In this post, we will learn how to solve Logical Reasoning Problems based on coins and matchsticks picking puzzles. To understand how exactly these kinds of puzzles look like, let’s start the post with a very simple example. The method to solve the example will give better insight so as to how to approach these puzzles. Two smart players A and B are playing a coin game in which they can pick up 1, 2, 3 or 4 coins. They have 78 coins and the player who picks the last coin will lose the game. A and B play alternately and A plays the first move. How many coins should A pick at first so h

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In a series of posts, we are going to cover the basics of some DI/LR topics. The first topic of discussion is Binary Logic. In a binary logic problem, we have people who either speak a true statement or a false statement. These people are divided into three categories: Truth-teller: This person will always speak the truth. All the statements made by this person are true. Liar: This person will always tell a lie. All statements made by this person are false. Alternator: This person always alternates between the truth and the lie. If first statement of this person is true, then se

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Data Interpretation questions typically have large amount of data given in the form of tables, pie charts, line graphs or some non-conventional format. The questions are calculation heavy and typically test your approximation abilities. A very large number of these questions check your ability to compare or calculate fractions and percentages. If you sit down to actually calculate the answer, you would end up spending more time than required and most of us can't afford to lose precious time during competitive exams like CAT, XAT, IIFT etc.  Here are few ideas that you can use for approxim

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We all know what factorials (n!) are. They look friendly and helpful but looks can be deceiving, as many quant problems have taught us. Probably it is because that Factorials are simple looking creatures, most students prefer attempting questions based on them rather than on Permutation & Combination or Probability. I will cover P&C and Probability at a later date but in today’s post I would like to discuss some fundas related to factorials, which as a matter of fact form the basis of a large number of P&C and Probability problems.   Some of the factorials that mig

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