In my last article, I had emphasized the importance of allocating equal time to each section of CAT or any MBA entrance exam. So, if the CAT 2009 duration was 135 minutes, then you should spend nearly 45 minutes per section. Knowing that you should devote 45 minutes to each section and hence also to the “Quantitative Ability” section, you should devise a process so as to make the best use of those 45 minutes. By the time you get to sit in CAT, you will have this knowledge about the general feel of the section (Mock Tests play a big role in this). If most of the questions you scan are very difficult to solve, try to identify at least 10 questions out of say 25 which you can reasonably attempt. Among those 10 questions, select those 7-8 which you know you can definitely crack it, by application of simple basic formulae. We call these problems to be sitters. Going by the previous experience, you will find that at least 1/3rd of questions can be attempted if one has a reasonable knowledge of the fundamentals. Divide those questions into 2 rounds of attempt. Higher number of questions has to be kept for round 1. The division will be based on
a. Identification of sitters
b. The level of comfort on a particular topic
There will be some questions which would seem pretty straight forward to you when you start but soon you would realize that there are twists to it. So what do you do if you have already spent 2-3 minutes on it? The only way out of this tricky situation is: just leave the questions and move forward. You have other questions from which to pick up questions and which can be easier ones.
Another strategy could be not to divide these questions into rounds, but identifying those 10 questions and solving them in one go. The Mock Tests play an important role in fixing a particular strategy. Although there is absolutely no substitute for knowing your theory, and practice, in QA section, there are some question-solving strategies that you may use. Some of these strategies are presented below:
1. You can substitute numbers for variables given in algebraic question. Some problems involve variables and we need to prove the validity of the expression. In such cases, the best method of solving them would be to assume values like 0, 1, etc for each of the variables given and substitute these in the expression. The example below substantiates this.
If a1 = 1 and an+1 – 3an + 2 = 4n for every positive integer n, then a100 equals
A] 399 – 200 B] 399 + 200 C] 3100 – 200 D] 3100 + 200
In this question we have the option of applying theories of progression or putting n = 1, 2 etc and then finding a trend. Let’s try the 2nd approach.
a1 = 1 and an+1 – 3an + 2 = 4n
Put n = 1. a2 = 4 – 2 + 3(1) = 5 = 32 – 2. This step is important as this will help us to identify the trend. Double check it by putting n = 2.
a3 = 4(2) + 3(5) – 2 = 21 = 33 – 6
Hence an = 3n – 2n. Hence the correct answer choice is [C].
2. There are quite a number of questions in CAT where only a basic scanning of the answer choices will lead us to the result. The example below substantiates this point.
The number of employees in Obelix Menhir Co. is a prime number and is less than 300. The ratio of the number of employees who are graduates and above, to that of employees who are not, can be
A] 101 : 88 B] 87 : 100 C] 110 : 111 D] 97 : 84
Hint to consider is that there is only one number in the question and we have to find the ratio, which means we have to scan the options. As the number of employees is a prime number, we can add the two numbers in each ratio directly to find the number of employees. Hence the total of the ratios in the 4 options comes out to be 189, 187, 221 and 181 respectively out of which only 181 is a prime number. Hence the correct answer choice is [D].
3. Interpretation and putting a data in a proper format saves you valuable time. Consider the example given below.
A chemical plant has four tanks (A, B, C and D), each containing 1000 liters of a chemical. The chemical is being pumped from one tank to another as follows:
From A to B @ 20 liters/ minute
From C to A @ 90 liters/ minute
From A to D @ 10 liters/ minute
From C to D @ 50 liters/ minute
From B to C @ 100 liters/ minute
From D to B @ 110 liters/ minute
Which tank gets emptied first and how does it take (in minutes) to get emptied after pumping starts?
A] A, 16.66 B] C, 20 C] D, 20 D] D, 25
Don’t write the data all over again. Just see the change happening in each tank and give proper signs to those changes. The change in the amount of chemical in each tank after every minute is as follows:
A: −20 – 10 + 90 = 60
B: −100 + 110 + 20 = 30
C: −50 − 90 + 100 = −40
D: −110 + 10 + 50 = −50
Since tank D loses the maximum amount of chemical in a minute, it will be emptied first. And it will take 1000/50 or 20 mins. Hence Option [C] is the correct one.
While you apply the above discussed strategies to solve the questions, many a times it is not possible to solve the questions by any of the technique discussed and then you are forced to solve it by traditional approach. At that time, you have to see whether traditional method will be too time consuming or not. If not, then you should solve that question. If it is too time consuming, then it is best to leave such question(s). You should know which questions to attempt and which not to. Only trying to attempt all the questions can be disastrous in CAT and other exams.
Remember that CAT has a habit of throwing surprises. But so is life. We have to be prepared for both of them.
Best of luck!
Dipak is an MBA from the prestigious IISWBM, Kolkotta – India’s Oldest B-School founded in 1953, and the home of learning for many a distinguished business leader. A QA faculty at MBAGuru, India’s fastest growing CAT Coaching Institute, Dipak is immensely popular among the students as much for his QA fundae as for his affable nature. Dipak also is a designated mentor for students seeking help with institute application forms and guidance.
An eventful, joyful & learning experience filled with some indelible memories. In brief, an awesome journey! The finest faculty, who seamlessly worked towards elevating my level and helping me develop a holistic outlook.
