Quant by Arun Sharma

MBA CAT 2024
3697
A simple one... But getting wrong answer!!!!!!!!!

if f(x)=f(x-2)-f(x-1)
and f(1)=0 and f(2)=1

1)what is the value of f(
a)0 b)-5 c)13 d)-9 e)-8

2) f(7)+f(4)

please explain ur approach..
i calculated f(3) f(4) and so on till f(..

just going by ur approach as a straight forward method, we can calculate the corresponding f(x) values
where we are getting f( 8 ) = 13
f(7)=-8 & f(4)=2
so f(7) + f(4) = -6+2 = -4

chandrakant.k Says
yeah thanku 😃 some silly mistakes which i always do ... btw is tat the normal approach??? or any other approach??


If you observe you can see that f(n)=*(n-1)th Fibonacci number......for n>1.....

So thats one more way to look at it.....but finding out nth Fibonacci is not easy for large n.....and hence the iterative method seems to be the simplest......
3698

If 6*x^2 + 6*y^2 = 13xy, what is the ratio of x to y ?

a) 2 : 3
b) 3 : 2
c) 4 : 5
d) 1: 2

OA A
My question is what is wrong with option B ?..even B satisfies the given equation..

3699

Help on this!!!
LOD2 from functions page number 389 p.no 41
if f(x)=1/g(x) then which of the following s correct?
a) f(f(g(f(x)))) = f(g(g(f((f(x)))))
b) f(g(g(f(f(x))))) = f(f(g(g(g(x)))))
c) g(g(f(f(g(f(x))))))= f(f(g(g(f((g(x))))
d) f(g(g(g(f(x))))) = g(g(f(f(f(x))))))
ufff type karne me hi itna mushkil hai, solve karne ki to door ki baat hai:p

3700

OA for this is B

Did this by assuming simple functions

Say f(x)= x
So, g(x)=1/x

Now go by options , u should get it in about 2 mins

But the problem here is, both option B and C satisfy.

So either the OA by arun sharma is incorrect, or my approach. But i dont see where i'm going wrong..Maybe you can figure that out

3701

can anyone help me with this?
prob 23 in lod iii progressions,'

if a n be the nth term.a 7 =15 ,then value of common diff that makes a 2 . a 7 .a 12 greatest?

3702
OA for this is B

Did this by assuming simple functions

Say f(x)= x
So, g(x)=1/x

Now go by options , u should get it in about 2 mins

But the problem here is, both option B and C satisfy.

So either the OA by arun sharma is incorrect, or my approach. But i dont see where i'm going wrong..Maybe you can figure that out


Thanks for ur approach. The OA given is c and even i m getting c. b i m getting LHS as
in (2)
f(g(g(f(f(x))))) = f(f(g(g(g(x)))))
f(g(g(f(x)))= f(f(g(g(1/x)
f(g(g(x)))= f(f(g(x)))
f(g(1/x))= f(f(1/x))
f(x)=f(1/x)
so not equal... hope i m correct...
3703

Can someone please help me out with this problem??

If 6*x^2 + 6*y^2 = 13xy, what is the ratio of x to y ?

a) 2 : 3
b) 3 : 2
c) 4 : 5
d) 1: 2

OA A
My question is what is wrong with option B ?..even B satisfies the given equation..
3704
ranjithreddy Says
Can someone please help me out with this problem??


You are right , both the options are correct.
3705

Please with explaination
solve the inequality
1) 2x^2+x+1>=0
2) 2x^2+x-1OA
1)
2) any value

one from fun
f(t)=(t-1)/(t+1) then f(f(t)) =
1) 1/t 2)-1/t 3)t 4) -t
i m getting -2/t 😛

3706
ranjithreddy Says
Can someone please help me out with this problem??



Both options satisfy. This can be arrived by simple observation of options . But incase you want to be doubly sure, reduce the equation to a quadratic in x or in y. It'll be of the form
6a^2-13a+6=0

Since coefficient of x^2 = Coefficient of constant term, we will get two roots which will be reciprocal, also since D>0, these roots happen to be real. So there shouldn't be any ambiguity whatsoever.
3707
Please with explaination
solve the inequality
1) 2x^2+x+1>=0
2) 2x^2+x-1OA
1)
2) any value

one from fun
f(t)=(t-1)/(t+1) then f(f(t)) =
1) 1/t 2)-1/t 3)t 4) -t
i m getting -2/t :p


Puys help on this!!!!
3708
If 6*x^2 + 6*y^2 = 13xy, what is the ratio of x to y ?

a) 2 : 3
b) 3 : 2
c) 4 : 5
d) 1: 2

OA A
My question is what is wrong with option B ?..even B satisfies the given equation..



Ya.....both A & B both satisfy this equation...........
3709

Originally Posted by chandrakant.k View Post
Please with explaination
solve the inequality
1) 2x^2+x+1>=0
2) 2x^2+x-1OA
1)
2) any value

one from fun
f(t)=(t-1)/(t+1) then f(f(t)) =
1) 1/t 2)-1/t 3)t 4) -t
i m getting -2/t



It should be [-1/2,1)

3710
Please with explaination
solve the inequality
1) 2x^2+x+1>=0
2) 2x^2+x-1OA
1)
2) any value


For 1st inequality,shouldn't it be any value??
For 2nd inequality,shouldn't it be (-1/2,1)
3711

Hi puys...GM...Can someone please help me out with this problem?
LOD 1...Time and distance


A starts from a point that is on the circumference of a circle, moves 600 metre in the North direction and then again moves 800 metre East and reaches a point diametrically opposite the starting point. Find the diameter of the circle?
a)1000 m
b)500 m
c)800 m
d)900 m

3712

1000 m??

Just form a pythagoras triangle, with the two sides as 600 and 800, while the hypotenuse is the dia of the circle

3713
Hi puys...GM...Can someone please help me out with this problem?
LOD 1...Time and distance


A starts from a point that is on the circumference of a circle, moves 600 metre in the North direction and then again moves 800 metre East and reaches a point diametrically opposite the starting point. Find the diameter of the circle?
a)1000 m
b)500 m
c)800 m
d)900 m

I think a)1000
3714

A starts from a point that is on the circumference of a circle, moves 600 metre in the North direction and then again moves 800 metre East and reaches a point diametrically opposite the starting point. Find the diameter of the circle?
a)1000 m
b)500 m
c)800 m
d)900 m

No need to do anything.As the question involves diameter and the numbers 800,600 the answer will be 1000.
3715
Please with explaination
solve the inequality
1) 2x^2+x+1>=0
2) 2x^2+x-1OA
1)
2) any value

one from fun
f(t)=(t-1)/(t+1) then f(f(t)) =
1) 1/t 2)-1/t 3)t 4) -t
i m getting -2/t :p


Inequalities::
1. Any value of X
2. [-1/2, 1)

Function::
f(f(t)) = -1/t


Thanks,
Gaurav K
3716

Arun Sharma: Chapter 18. Questions 37 and 39

A newspaper agent sells TOI, HT, IN in equal numbers to 302 persons. Seven get HT and IN, 7 got HT and IN, 12 get TOI and IN , 9 get TOI and HT and 3 get all the three newspapers.

Question number : 37 .
What percent get TOI or HT but not IN?

Question number : 39 .
The difference between the number reading HT and IN only and HT only is?