Commonsense Aptitude Test

 | April 10,2010 12:37 pm IST

Every youngster knows which mobile offers best value, with all complicated data on talk-time, free SMS, rate of local call, the pulse, etc., taken into account.

Why does a simple similarquestion based on ratio proportion or unitary method looks so confusing inside the CAT exam room?


Have you ever seen a child of III or IV standard committing a calculation mistake, while buying toffees or chocolates? Why does he commit a mistake while doing a similar question in CAT, after studying maths for another decade?


Even an illiterate lady would know exactly how many more potatoes she must get, if subziwala doesn't have the change of say, Rs. 1.50, to return. Why then a learned graduate is at sea to find this out with a paper and pen?

The answer to all these paradoxes is simple. In the former situations, Commonsense is used, and in the latter, Maths.


Let's take an example. In this season of "sale" every where, you find on one shop a board that says "Buy 3, get 1 free". And on the nearby shop "Get 30% off".  Ask the students in a maths class to find out the better offer and they are zapped. Many of the mathematicians will promptly find the discount in the first case to be 33.33 % and in the other to be 30%, thus declaring the first offer better. However, a little common sense (which somehow appears only when you are in the market and disappears as soon as you enter the class room!!!) would tell that in the first case, you are getting a discount of 25%, as you are not paying for 1 out of 4.


Now, ask someone to find out the sale price when an object costing Rs. 151.25 is sold at a loss of 130%. The mathematician will enter the jungle of formulas and calculation, while the one with commonsense (a rare species!!!) would know that nothing could be sold at a loss of more than 100%. Even if you give something free to someone the loss is 100%. And even if you spend something further on its disposal, that is added to the cost and the percentage loss still remains 100%.


The section on quantitative ability in CAT (and other competitive exams also) now shows a shift towards questions having greater element of commonsense rather than pure maths(this might have something to do with paper-setters having more commonsense!!!). This doesn't mean that we don't need formulas and calculations now, but that we use calculations or formulas in the situation when logical thinking (a euphemism for commonsense!!!) needs to be supplemented with these and we don't rush to the formula at the sight of the questions.


Before you enter the CAT room, the invigilator would instruct you to keep calculators and other helping gadgets (so desperately required near the half time!!!) out. Fortunately, there is no instruction to keep the commonsense out. So, take it along and use it profusely. This could be your best bell (oops, bet) for the CAT.