January 30th, 2014 by Ravi Handa

If you have written CAT earlier, then probably you should skip this post. This is mainly directed towards those who are planning to write CAT and do not know what all gets covered in the exam.
CAT is divided into two sections:
1. Quantitative Aptitude and Data Interpretation
2. Logical Reasoning and Verbal Ability
Looking at the data of past few years, both sections have 30 questions each. A student is given 70 minutes for each section.
Quantitative Aptitude (20/21 questions) is basically questions which test your mathematical prowess. It can be further classified into 5 broa

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Posted in CAT, General Funda

January 22nd, 2014 by Ravi Handa

A team of miner planned to mine 1800 tonnes in a certain number of days.Due to some difficulties in one third of the planned days, the team was able to achieve an output of 20 tons of ore less than the planned output.To make up for this, the team overachieved for the rest of the days by 20 tons.The end result for this that they completed the one day ahead of time.How many tone of ore did the team initially plan to ore per day?
a. 50
b. 100
c. 150
d. 200
e. 250
Answer :
Let us assume the no. of days as '3d' and the output per day as 'x'
T

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Posted in Solved Examples

January 22nd, 2014 by Ravi Handa

Question : a, b and c are the sides of a triangle. Equations ax^2 + bx + c = 0 and 3x^2 + 4x + 5 = 0 have a common root. Then angle C is equal to??
Answer : Roots of 3x^2 + 4x + 5 = 0 are complex i.e. they are of the form (p + iq) & (p - iq) where i is iota = sqrt(-1)
For a quadratic equation, complex roots occur in conjugate pairs if the coefficients are real.
In the equation, ax^2 + bx + c = 0, the coefficients are sides of a triangle and hence real. So, if one of roots is common with the other equation say (p+ iq) then the other root will

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Posted in Solved Examples

January 22nd, 2014 by Ravi Handa

Question : A person lent out some money for 1year at 6% per annum simple interest and after 18months he again lent out the same money at a simple interest of 24% per annum. In both cases he got Rs.4704. What was the amount that he lent out if interest is paid half yearly?
a. Rs 4000
b. Rs 4200
c. Rs 4400
d. Rs 3600
Answer :
In the first case, the rate of interest is 3% per half-year. The money will become
1.03x after 6 months from t = 0
1.06x after 12 months from t = 0
1.09x after 18 months from t = 0
1.12x after 24 months from t = 0 and so on ....

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Posted in Solved Examples

January 22nd, 2014 by Ravi Handa

Question : Six persons try to swim across a wide river.Its known that on an average only three persons out of 10 are successful in crossing the river.Whats the probability that at most four of the 6 persons will cross the river safely?
Answer :
The probability distribution of the random variable X is called a binomial distribution, and is given by the formula:
P(X)= nCr * p^r * q^(n-r)
where
n = the number of trials
r = 0, 1, 2, ... n
p = the probability of success in a single trial
q = the probability of failure in a single trial
(i.e. q = 1 âˆ' p)
Keeping th

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Posted in Solved Examples

January 22nd, 2014 by Ravi Handa

Question : The L.C.M of 5/2, 8/9, 11/14 ?
Answer :
LCM = LCM of Numerator / HCF of Denominator
HCF = HCF of Numerator / LCM of Denominator
So,in this case;
LCM (5/2, 8/9, 11/14) is :
LCM (5,8,11) / HCF (2,9,14) = 440 / 1 = 440

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Posted in Solved Examples

January 22nd, 2014 by Ravi Handa

The concept of ‘divide and conquer’, derived from the Latin phrase ‘Divide et impera’, was put into use effectively by everyone from Caesar to Napoleon to The British in India. Even Gaddafi tried using the same but as current events show us – he wasn’t very effective. Dividing rather divisibility rules to be specific can come in really handy at times in solving problems based on Number Systems.
The standard rules which nearly all of us are very comfortable with are the ones for 2n and 5n. For these all that one needs to do is look at the last ‘n’ digits of the number. If the

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Posted in CAT, IBPS, IIFT, Quant Funda, SBI, SNAP, XAT

January 22nd, 2014 by Ravi Handa

Factor Theory
I understand that the title might be a little misleading but at least I could not come up with something better. So before you end up getting disappointed, let me first list down the topics that I am going to cover in this particular blogpost:
Number of factors of a given number
Number of even factors or odd factors of a given number
Sum of all factors of a given number
Sum of all even factors or odd factors of a given number
We know that a number N can be written as a product of its factors as given below
N = ap x bq x cr …
Here a,b

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Posted in CAT, IBPS, IIFT, Quant Funda, SBI, SNAP, XAT

January 22nd, 2014 by Ravi Handa

Dealing with Factorials
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.

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Posted in CAT, IBPS, IIFT, Quant Funda, SBI, SNAP, XAT

January 22nd, 2014 by Ravi Handa

Number of Trailing Zeros
In this blog post, I would like to cover these two ideas:
Number of trailing zeroes in an expression
Number of trailing zeroes in 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 occassions 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 number of e

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Posted in CAT, IBPS, IIFT, Quant Funda, SBI, SNAP, XAT