Quant by Arun Sharma

Sum of first N natural numbers=n(n+1)(2n+1)/6
The number of times K is divisible by 4= number of times M is divisible by 8 + number of times M+1 id divisible by 8
=6+7=13 So answer is none of these.

Can anyone help me out with these?

1. Define a number K such that it is the sum of the squares of the first M natural numbers (k = 1^2 +2^2 + 3^2 .....+M^2) where M
a) 10 b)11
c)12 d)none of these

2. Find the 28383rd term of series 123456789101112....

a)3 b)4
c)9 d)7


First one I don't have a clue, don't know how to proceed further from K=m(m+1)(2m+1)/6.

And the second one I am getting answer 3 whereas books says 9.

Me too got the same answer for that 2nd digit of 7372
that is 3

Can anyone help me out with these?

1. Define a number K such that it is the sum of the squares of the first M natural numbers (k = 1^2 +2^2 + 3^2 .....+M^2) where M
a) 10 b)11
c)12 d)none of these

2. Find the 28383rd term of series 123456789101112....

a)3 b)4
c)9 d)7


First one I don't have a clue, don't know how to proceed further from K=m(m+1)(2m+1)/6.

And the second one I am getting answer 3 whereas books says 9.
Sum of first N natural numbers=n(n+1)(2n+1)/6
The number of times K is divisible by 4= number of times M is divisible by 8 + number of times M+1 id divisible by 8
=6+7=13 So answer is none of these.



Thanks dude but answer in the book says 12. This is sum no 61 of LOD 2 numbers. Although the answer may be wrong.

Do you need more explanation?

subho_86 Says
Thanks dude but answer in the book says 12. This is sum no 61 of LOD 2 numbers. Although the answer may be wrong.

And yeah about the second problem. The book answer has to be wrong. Even I got 7372.

Btw how did you do it. I did it by the long method. Any good ones?

my method:

1 digit nums 1-9 = 9*1=9
2 digit nums 10-99 = 90 *2=180
3 digit nums 100 - 999 = 900*3 = 2700

Total = 2700+180+9 = 2889

Hence now we have to find 28383-2889 = 25494 term of the series 1000 1001 1002........

Divide by 4 we get 6373 quotient and 2 remainder.

Hence 1000 is first term 6373rd term = 1000+6372 = 7372.

Now next term is 7373. As rem = 2 we need the 2nd digit which is 3.

Any better method?

bibinvarghese Says
Do you need more explanation?


No I understood your method perfectly.

My method also was the same.

And yeah about the second problem. The book answer has to be wrong. Even I got 7372.

Btw how did you do it. I did it by the long method. Any good ones?

my method:

1 digit nums 1-9 = 9*1=9
2 digit nums 10-99 = 90 *2=180
3 digit nums 100 - 999 = 900*3 = 2700

Total = 2700+180+9 = 2889

Hence now we have to find 28383-2889 = 25494 term of the series 1000 1001 1002........

Divide by 4 we get 6373 quotient and 2 remainder.

Hence 1000 is first term 6373rd term = 1000+6372 = 7372.

Now next term is 7373. As rem = 2 we need the 2nd digit which is 3.

Any better method?

It is 26
that is 58!-38!=37!*38*(39-1)*40...........................58

Number System LOD 2 Ques.No: 74

what is the highest power of 3 available in the expresion 58!-38!?
a)17 b)18 c)19 d)none of these


Ans is given as a)17

this is how i did the sum....
58! contains 27 3's.
38! contains 17 3's.

so 58!-38! will have 27-17 = 10 3's. But that is not the correct answer according to the book....

help me out....


Thanks in advance....

cheerz
vidhyasagar

92) taking out and removing 6!
(14*7+14(7*8*9.....13))/(112-21)
=14*7(1+8*9*.........13)/91
=14*7(1+8*9*.....13)/13*7
=reminder(14/13)=1

puyz help me out in des problemz...
numbers-lod2
89)The computer takes input of a no. N & a X where X is a factor of no. N.In particular case N is equal to 83p796161q and X is equal to 11 where 0

2^44 refer binomial therom

Number System LOD 2 Ques.No: 62


Number System LOD 2 Ques.No: 71
X and Y are 2 positive integers. Then what will be the sum of coefficients of the expansion of the expression (X+Y)^44?
a) 2^43 b)2^43+1 c)2^44 d)2^44-1


Please explain the answer guys....

thanks in advance

Cheers
vidhyasagar

If you divide a fraction by a particular number ie downgrade then the remainder must be multiplied by the same number at the end to get the actual remainder ie upgrade. See my soln. The answer in the book is also 7!




92) taking out and removing 6!
(14*7+14(7*8*9.....13))/(112-21)
=14*7(1+8*9*.........13)/91
=14*7(1+8*9*.....13)/13*7
=reminder(14/13)=1

Answer of 92.

14. 7! + 14 .13!
2.8! -21.6!

= 14(7! +13!)
6!(2.8.7 -21)

= 14( 7!+13!)
91(6!)

=14(7!+13!)
7!(13)
= 14.7! + 14.13!
7!.13 7!.13
= rem 7! + rem 0
= rem 7 !
ans

I admit my mistake

subho_86 Says
If you divide a fraction by a particular number ie downgrade then the remainder must be multiplied by the same number at the end to get the actual remainder ie upgrade. See my soln. The answer in the book is also 7!

Question no. 1. Find the remainder when 73 * 75 * 78 * 57 * 197 is divided by 34.
a) 32 b)30 c)15 d) 28

Question no. 2 Find the least number that when divided by 16,18 and 20 leaves a remainder 4 in each case, but is completely divisible by 7.
a) 364 b)2254 c)2964 d)3234 e)2884

question no. 3 If 2
options are 6, 7, 8 and 4

#newbie

Numbers Lod-II

86) Find the remainder when 7^99 is divided by 2400.

a) 1 b) 343 c)49 d)7

Question no. 1. Find the remainder when 73 * 75 * 78 * 57 * 197 is divided by 34.
a) 32 b)30 c)15 d) 28

Question no. 2 Find the least number that when divided by 16,18 and 20 leaves a remainder 4 in each case, but is completely divisible by 7.
a) 364 b)2254 c)2964 d)3234 e)2884

question no. 3 If 2
options are 6, 7, 8 and 4

#newbie


Question no 1:

= 73 * 75 * 78 * 57 * 197 / 34

taking remainders
= 5 * 7* 10*(-11)*(-7)/34
= 35*(-70)*(-7)/34
= 1*(-2)*(-11)/34
=22/34

Remainder = 22. Hence either the data is wrong or the options are wrong.

Question no 2: Check the divisibility of the options. You will get it easily. I am not going to do it.

Question no 3:
upper limit of x+y is when x=4 and y = 3 ie 7

lower limit of x-y is when x=2 and y=3 ie 2-3 = -1

Hence ratio is 7/-1 = -7

Taking only the magnitude it is 7.

can anyone lemme knw whts the shortest way to find last two digits of an expression like

67*56*71*55*70*35*44

Thanks
;-)

lod-2-numbers

91)What is the rightmost digit preceeding the zeros in the value 20^53

75)Reamainder when 22334^(1^2+2^2+......+66^2) is divided by 5.

see the cyclicity of 2
is 4
53=13*4+1
so rightmost digit is 2

22334=22330+4
22334^2 gives a remainder 1 on division by 5

now we see the power
its 66.67.133/6=11.67.133 that means an odd no

remainder 1.4 =4
as we can write the term as 22334.(22334^2)^k


yaar implex i coudnt get u....
its asked....20^53
how can u take 2^53..nd solve for rightmost digit preceeding the zeros
is it smethin like...u have taken 2^53 and 10^53 seperatly can u b more clear....
Numbers Lod-II

86) Find the remainder when 7^99 is divided by 2400.

a) 1 b) 343 c)49 d)7


Answer is b)343

7^4n+3 /2400
=> 1* 7^3/2400 ( as 7^4= 2401, 1 remainder left)
=> 343 is remainder