Maths Session 3

Synopsis of 2 sutras in Vedic mathematics

Lets get down to business. Let us see some magic of vedic mathematics to make our life simple. In the following sessions, we will try to cover 16 sutras of Vedic mathematics which will eventually help you in calculating faster. This is very essential for CAT quants & DI section.

1. All from 9 and the last from 10

For example 1000 - 357 = 643

We simply take each figure in 357 from 9 and the last figure from 10.

So the answer is 1000 - 357 = 643

And that is all there is to it! This always works for subtractions from numbers consisting of a 1 followed by noughts: 100; 1000; 10,000 etc.

Similarly 10,000 - 1049 = 8951







Vertically and crosswise

Suppose you need 8 x 7

8 is 2 below 10 and 7 is 3 below 10. Think of it like this:






The answer is 56. The diagram below shows how you get it.





You subtract crosswise 8-3 or 7 - 2 to get 5, the first figure of the answer. And you multiply vertically: 2 x 3 to get 6, the last figure of the answer.

Suppose you want to multiply 88 by 98. You can give the answer immediately, using the same methods above. Both 88 and 98 are close to 100.88 is 12 below 100 and 98 is 2 below 100.

You can imagine the sum set out like this:







As before the 86 comes from subtracting crosswise: 88 - 2 = 86 (or 98 - 12 = 86: you can subtract either way, you will always get the same answer).And the 24 in the answer is just 12 x 2: you multiply vertically. So 88 x 98 = 8624

103 x 104 = 10712

The answer is in two parts: 107 and 12, 107 is just 103 + 4 (or 104 + 3), and 12 is just 3 x 4.

Similarly 107 x 106 = 11342 : 107 + 6 = 113 and 7 x 6 = 42

Look at another example:






Multiply crosswise and add to get the top of the answer: 2 x 5 = 10 and 1 x 3 = 3. Then 10 + 3 = 13. The bottom of the fraction is just 3 x 5 = 15. You multiply the bottom number together.

So:






Subtracting is just as easy: multiply crosswise as before, but the subtract:






More in next session. Till then, do write me for any clarification…


By:
Arjun Pal
(Knowledge Cell - Globsyn Business School)

Tackling English

Well, it is inevitable to compare CAT with cricket as there are so many analogies that can be drawn. As even at the last few minutes hard working & luck to find out the easy questions during the exam can be compared with the last ball of the last over in perfectly competitive match.
When you look at the English section of a CAT paper, there are two variables which help you maximize your score viz Attempts and Accuracy. Neatly juggling these two parameters will help one score the marks that would be required to get a good score in English.
For an English section, it is prudent to go slow in a paper which has more easy questions as the accuracy percentage in an easy paper (for the easy questions) would be higher and hence taking unnecessary risks (there will still be difficult questions) in the paper would reduce this overall accuracy thereby making your score relatively lower than others' scores.If the English section is difficult, then try to maximize the attempts and if it is easy, then concentrate on accuracy.
The broad classification for the English section can be viewed as RC (Reading Comprehension) & Non-RC sections. A good balance between the two can be made to create an impressive score in this section.
Attempting RC based questions will be much easier as we can easily guess the meaning of unknown words. Also, with the help of regular practice, speed reading can be adapted so that we can make ourselves strong enough in solving RC. Much space is there for guess work in RC.
Questions in Non-RC section are based on English grammar, though IFJ (Inference-Fact-Judgment) or Puzzle based questions are also common. These are binary type questions as you can answer these only if you know it. Guess work is not possible or proved to be highly risky.
Following table shows the trend for this section:



CAT 2007 had 25 questions in this section. A good attempt of around 15 questions had helped people to reach the cut off.
The clear fact arises is that RC, on an average contributes to 50% of total questions in CAT. The expected number of RC in this year will be 2. We advice our readers that they should try to attempt both RC, if possible.
Jumbled paragraphs will be an area of interest for the paper setters as this is frequently used as a speed breaker. Practice this section to get sure shot marks in these questions.
Try to go through major English newspapers daily as this will improve your ability of speed reading. Take a target of solving 3 RC a day in 15 minutes.
Best of Luck !!!

By:
Arjun Pal
Knowledge Cell - Globsyn Business School

Improvement in Reading Speed and Comprehension (Verbal Ability)

Quite often a CAT aspirant must be wondering as to how one manages to answer so many questions in such a short span of time. There is no doubt that one needs to be very well prepared through regular practice and covering wider and wider range of sample problems. But there is one additional way by which one can help the cause – by improving his speed of reading. This may sound incredible to start with but if we look at the facts, the real picture will emerge.

An average person can read 150 to 200 words in a minute with a comprehension level of 60% by concentrating hard and his performance can be termed satisfactory. According to experts, an average reader is nearly five times slower than a good reader and if we consider reading efficiency, the gap is even wider. Reading efficiency is defined as reading speed multiplied by comprehension rate called efficient words per minute (ewpm). For an average reader, this is typically about 120 ewpm while for top readers this can be as high as 850 ewpm. A reasonably good reader can achieve a reading efficiency of about 300 ewpm – i.e., 2.5 times the speed of an average reader. Let us now examine the impact this has on a person sitting for CAT. The average time taken to read a question by the average reader is 15 – 20 seconds while this will come down to 6 – 8 seconds for s good reader. Thus a person can get nearly 15 minutes extra for answering the entire examination.

It therefore pays to improve the speed of reading. But how does one do it? To start with, you may take a on line test to measure your current status by visiting http://www.readingsoft.com/ or http://www.freereadingtest.com/

There are important areas for improvement like in the areas of Eye movement, Eye span, etc.

Some good tips regarding how to improve your reading speed are available at http://www.mindtools.com/speedrd.html and free software (trial basis) are also available for download at http://www.rocketreader.com/download/RocketReaderDownload.html. There are many websites which help in improvement in English vocabulary, comprehension and reading speed.

By:

Prof. Bikramjit Sen

IIM C Batch 08

How to Speed Read?

CAT has a section called Reading Comprehension. Reading Comprehension tests your ability to read a document and take out the most important points in a very short time.

Reading Comprehension section expects you to read a particular prose and answer some questions based on that prose. Advantage of this section is that if you can read and understand that particular prose you can answer a number of questions at one go. This helps you to increase your number attempted in the test. Downside is if you waste too much time reading and understanding then the time taken for answering each question may become disproportionately high.

Therefore to successfully crack Reading Comprehension (RC) you need to speed read. Speed Reading is a technique by which you can pick up the salient points in a prose without reading each and every word. Practicing speed reading will help you to scan a prose fast and comprehend the basic points the author is trying to convey.

To practice speed reading you first need to read the entire prose word by word. Then mark the relevant words in the text which you feel are most important and without which you would be unable to comprehend the paragraph. Then read those words only. See whether you are able to answer all the questions by only reading the underlined words. Once you have done this a few number of times you would start automatically read the relevant section of the text passage and your speed reading competency would increase. Slowly reduce number of words you need to read in a passage till such time you hit your basic minimum. Remember speed reading is a very individualistic exercise. The number of words you need to read to understand the passage may vary from your friend.

Practice the above mentioned technique for next 1 month and you will see a drastic improvement in RC scores.

By:

Prof. Debdutta Choudhury

IIM C – batch 37