Quantative Ability CAT Questions
November 7th, 2009 Posted in Daily Question & Gyan
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1. If x & y are positive integers such that (3x + 7y) is a multiple of 11, then which of the following of will also be divisible by 11?
a. 4x + 6y
b. x + y + 3
c. 4x – 9y
d. 9x + 4y
2. Ram and Mohan solved a problem of quadratic equation. While solving, ram made a mistake in the constant term and thereby got the roots as 8 and 2 whereas Mohan made a mistake in the coefficient of x and obtained -9 and -1 as the roots. What are the correct roots of the equation?
a. 8, -1
b. -9, 2
c. -8, -2
d. 9, 1
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Tags: CAT 2009 Math Questions, CAT 2009 Quant Questions, CAT Quantitative Ability Test for MBA, CAT Sample Quantitative Ability Questions, CAT Sample Quantitative Questions, Quantitative Ability, Quantitative Ability Questions, Quantitative Ability Sample Questions for CAT, Quantitative Questions and Answers, Sample Quantitative Ability
November 7th, 2009 at 1:23 am
1 c
2 d
November 7th, 2009 at 1:59 am
1) c
2nd not getting plz help
November 7th, 2009 at 6:17 am
1) c 2 )d
1) take x= 10 and y = 2. The given expression is divisible by 11
4x+6y = 40+12 = 62 is not divisible by 11
x+y+3 = 10+2+3 = 15 is not divisible by 11
4x-9y = 40 – 18 = 22 is divisible by 11
9x+ 4y = 90 + 8 = 98 is not divisible by 11
2)let the equation is x^2 + ax + b = 0.
Ram didn’t make a mistake in coefficient of x.
so a = -(8+2) = -10
Mohan didn’t make a mistake in constant term.
so b = -9 * -1 = 9
so the equation will become x^2 -10 x + 9 = 0
=> (x-1)(x-9)= 0. Therefore 1 and 9 are the roots of the equation.
November 7th, 2009 at 7:10 am
first question ans is b
3x+7y should be divisible by 11
so put x=3andy=5
we get 3×3+7×5=44
it is divisible by 11
then option b i.e. x+y+3
we will get 11 by summation of these digits.
November 7th, 2009 at 7:39 am
Equation can be written also as follows,
X^2-(sum of the roots)*X+(product of the roots)=0
so the general equation can be written as,
X^2+(b/a)X+(c/a)=0
so,
sum of the roots =-b/a
prod of the roots = c/a
by this way use ram’s value to find the sum.
& mohan’s value to find the prod.
ans is (9,1)
November 8th, 2009 at 10:58 pm
1) c
2) d
November 8th, 2009 at 11:01 pm
1. c
(3x + 7y) is a multiple of 11. For x = 5 & y = 1 we get 3x + 7y = 22 i.e. a multiple of 11. We will put this set of values of x & y & check whether the value of the expression is a multiple of 11 or not. Only (4x – 9y) gives 11.
2. d
Ram solved the equation (x – 8)(x – 2) = 0, x^2 – 10x + 16 = 0, in which 16 is not correct. Mohan solved (x + 9) (x + 1) = 0, x^2 + 10x + 9 = 0, in this coefficient of x is not correct. So the correct equation is x^2 – 10x + 9 = 0, (x – 9)(x – 1) = 0, x = 1, 9.
November 9th, 2009 at 2:15 am
1.c
2.d
November 9th, 2009 at 5:53 am
In 1, if we take x=3, y=5
then 3x+7y=44, divs by 11.
putting these values in the options,
x+y+3=11, 4x-9y=-33
Both divs by 11
EXPLAIN….
November 10th, 2009 at 5:57 am
1 d
2d
November 11th, 2009 at 10:43 am
1c
2d