Official Quant thread for CAT 2013

@nole said:
ram wrote first 50 natural numbers on a black board.Then he erased two numbers sayp and q ,and replaced them by a single number N,he performed this operation repeatedlyuntil a single number was left.For all odd values of n,in nth operation,he choose N to bep+q+1,and for all even values of n he choose N to be p+q-1,find the final number whichremainedfind the remainder when 6^65^56 is divided by 43.
1st question is ambiguous....are we talking about the nth operation here?? pls clarify.

for 2nd ques it should be 6...
e(43) is 42...
65^56%42
e(42) is 12
56%12 = 8..
23^8%42 = 25^4%42 = 25..
6^25%43 = 36^5%43 = 6...
@nole said:
ram wrote first 50 natural numbers on a black board.Then he erased two numbers sayp and q ,and replaced them by a single number N,he performed this operation repeatedlyuntil a single number was left.For all odd values of n,in nth operation,he choose N to bep+q+1,and for all even values of n he choose N to be p+q-1,find the final number whichremainedfind the remainder when 6^65^56 is divided by 43.
total operations will be 49
hence last no wil be n(n+1)/2 -1=25*51+1=1276

6^65^56 mod 43
E(43)=42
65^56 mod 42
E(42)=42(1/2)(6/7)(2/3)=12
65^8 mod 42
42 = 6*7
65^8 mod 6=1
65^8 mod 7=4

6a+1=7b+4
6a=7b+3
b=3
hence it is 24 mod 45
6^24 mod 43
7^12 mod 43
6^6 mod 43
(-7)^3 mod 43
-343 mod 43
1


@mailtoankit said:
sir, do ans aa rahe hai...rt(8+4rt3) and rt(8-4rt3)...to first one nahi hona chahiye??
Nahin ek hi hai, minus waala (square it and see). I typed plus by mistake 😃 Will edit...

regards
scrabbler

@scrabbler if i take numbers to 1,2,3,4,5,6,7,8,9,10.....

then for odd (1 and 3) their summation is (3+1)+1 i.e 5
similarly for even ie (2+4)-1 i.e 5 so while traversing first time we may have +1 , -1 but in second traversing all values are coming odd 5,5,11(5+7+1),13(8+6-1),13 etc.

so m not getting how only +1 would be added finally ?
@Subhashdec2 m sorry,but i don't know what is E() ? can u explain.
@nole said:
@scrabbler if i take numbers to 1,2,3,4,5,6,7,8,9,10.....then for odd (1 and 3) their summation is (3+1)+1 i.e 5similarly for even ie (2+4)-1 i.e 5 so while traversing first time we may have +1 , -1 but in second traversing all values are coming odd 5,5,11(5+7+1),13(8+6-1),13 etc.so m not getting how only +1 would be added finally ?
It is for the nth operation n is even or odd, not for the sum being even or odd at that stage. That's why I clarified. Go check the original post, it has been updated...

So 1st op mein 1 adds, 2nd mein subtracts and so on. At least, that's my interpretation.

regards
scrabbler

@nole said:

find the remainder when 6^65^56 is divided by 43.

6?
E(43) = 42
6^42k mod 43 = 1
65^56 mod 42 ---> E(42) = 12
65^8 mod 42 = 25
6^25 mod 43 = 6*(6^3)^8 mod 43 = 6*(1)^8 mod 43 = 6

@scrabbler said:
It is for the nth operation n is even or odd, not for the sum being even or odd at that stage. That's why I clarified. Go check the original post, it has been updated...So 1st op mein 1 adds, 2nd mein subtracts and so on. At least, that's my interpretation.regardsscrabbler
han yehi hoga...otherwise the question is kind of weird...that is what i was trying to clarify

net effect +1 hoga...hence the answer 1276, which u already explained..
Given 6 segments whose length are the elements of the set S={2,3,5,8,13,21} , what is the number of distinct triangles that can be formed using any three of these segments?
a. 210 b. 5040 c. 6 d. 10 e. 0
@Logrhythm
@scrabbler yes the answer is 1276, thanks.
@mailtoankit yes it 6,can u explain what is e(43)=42 ? Is it some theorem ? what is E sign there?
@pankaj1988 said:
Given 6 segments whose length are the elements of the set S={2,3,5,8,13,21} , what is the number of distinct triangles that can be formed using any three of these segments? a. 210 b. 5040 c. 6 d. 10 e. 0
0 since no two smaller add up to more than a third larger one.

regards
scrabbler

@nole said:
@mailtoankit yes it 6,can u explain what is e(43)=42 ? Is it some theorem ? what is E sign there?
yes, Euler function....go to totalgadha.com...there you will find every thing about euler
@pankaj1988 said:
Given 6 segments whose length are the elements of the set S={2,3,5,8,13,21} , what is the number of distinct triangles that can be formed using any three of these segments? a. 210 b. 5040 c. 6 d. 10 e. 0
0 ?
@pankaj1988 said:
Given 6 segments whose length are the elements of the set S={2,3,5,8,13,21} , what is the number of distinct triangles that can be formed using any three of these segments? a. 210 b. 5040 c. 6 d. 10 e. 0
0...it does not satisfy the condition a+b > c
where a,b and c are the sides of the triangle...
@bs0409 said:
In the xy-plane, if points (5, 2), (2, 5), and (-2, -5) are the vertex of a parallelogram, how many such parallelograms are possible?(A) 1(B) 2(C) 3(D) 4(E) 6
3.
try to place the fourth vertex opposite each given points and form the figure.
@pankaj1988 said:
Given 6 segments whose length are the elements of the set S={2,3,5,8,13,21} , what is the number of distinct triangles that can be formed using any three of these segments? a. 210 b. 5040 c. 6 d. 10 e. 0
zero!
fibonacci series... a+b=c
but for triangles to exist.. a+b>c
@nole

E means Euler

Theory: If M and N are two Numbers co-prime to each other, i.e. HCF(M, N) = 1 and N=a^p*b^q*c^r...., Remainder[M^o(N)/N] = 1, where, o(N)= N(1 - 1/a)(1 - 1/b)(1 - 1/c)... and is known as Euler's Totient Function..o(N), or, E(N) is also the number of Numbers less than and prime to N..

Given, Rem[6^65^56/43] =?

Nw, E(43) = 42(1 - 1/43) = 42..

Thus, Rem[6^42/43] = 1..Since the power is 65^56, we will have to simplify this powers in terms of 42k + r. Therefore, we need to find the remainder when 65^56 is divided by 42..

Rem[65^56/42]=?..Here, E(42) = 12...Thus, Rem[65^12/42] =1, or, Rem[65^48/42] =1

Thus, Rem[65^8/42] = Rem[35^4/42] = Rem[29^2/42] = 1

Thus, 6^65^56 = 6^(42k + r) = 6^42k*6

Rem[6^42k*6/43] = 6..
@pankaj1988 said:
Given 6 segments whose length are the elements of the set S={2,3,5,8,13,21} , what is the number of distinct triangles that can be formed using any three of these segments? a. 210 b. 5040 c. 6 d. 10 e. 0
option e -0

@realslimshady said:
How long is the side of the largest equilateral triangle that can be inscribed in a square whose side has length 1?A. 1B. √5/2C. 3√5/4D. 2-√3E. √(8-4√3)Please show your approach.

@scrabbler isnt option E less than 1.. its approx .8 in value..