BRAIN STRAIN !!!

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Incognito
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Q1) How many three digit no's  in base 11 are possible, when expressd in base 9, has its digit reversed?

Q2) Find no. of integral solutions of eqn a*b*c*d = 4 ?

Q3) Find no. of ways in which three no's in A.P. can be selected from first 51 natural no's?

Q4) Find the remainder of (19^92)/92 ?

 

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Answers

 

Answer Q4.
Reminder of (1992)/92 =  Reminder of (36146)/92
= Reminder of [(368-7)46] / 92
=  Reminder of (7)46 / 92

and after calculations I get the answer as 49.

Answer Q2. Find no. of integral solutions of eqn a*b*c*d = 4 ?

4 = 2 x 2 x 1 x 1
  = 1 x 4 x 1 x 1
For case 1 No of Possibilities = 4!/(2! 2!) =6
For case 2 No of Possibilities = 4!/(3! ) =4
so total number of solutions 6 + 4 = 10

 

Q3) Find no. of ways in which three no's in A.P. can be selected from first 51 natural no's?

Let the common differnce be 1
Possible A.P are 1,2,3 | 2,3,4 | . . . . . . . | 49, 50, 51
So number of possible APs with common differnce 1 = 49
Similarly, number of possible APs with common differnce 2 = 47
                  number of possible APs with common differnce 3 = 45
                 . . . . . . . .
                  number of possible APs with common differnce 25 = 1
Total = 1 + 3 + 5 . . . . + 49 (25 terms)
Sn = N/2 x [2a + (n-1)d]
        = 25/2 [2 + 24 x 2 ]
         = 25 x 25 = 625
  

 Could you please Check Question number 1 ? ? ?is there any TYPO???

 

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ques 3 : for three naturl

ques 3 :

for three naturl numbers to be AP , the sum of the first and last nos. must be even

out of first  51 natural nos 26 are odd and 25 are even.

hence the total possible ways 26C2 + 25C2 =  325 + 300 = 625

i THINK THIS IS A lot easier solution.

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ques :  92 = 23 * 4 19 =

ques :  92 = 23 * 4

19 = 23-4

(23-4)92 = 2392 + 492  + k*92

2392 = x mod(23*4)                                       492 = y mod(23 *4 )

2391 = x/23 mod(4)                                       491 = y/4 mod(23)

cyclicity = 2                                                       2182 = y/4 mod(23)

thus x/23 = 3                                                   cyclicity = 22

x = 69                                                                thus y/4 = 18

                                                                            y  = 72

 

thus remainder = (72+69) mod 92 = 49

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chinese remainder theorem

hello rajorshi,

i am very weak in maths..

plz help me out with the chinese remainder theorem

i hv gone thru d proof but not able to understand anything..

i would really appreciate if u kindly explain the theorem.

Thanks,

sonal

Incognito (not verified)
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Qn no.1 is absolutely

Qn no.1 is absolutely fine..i',ve checked it..m giving u the options also..& solutn to qn no.2 is wrong.

Q1) How many three digit no's  in base 11 are possible, when expressd in base 9, has its digit reversed?

a)1   b)2   c)3   d)4

Q2) Find no. of integral solutions of eqn a*b*c*d = 4 ?

a)80   b)76  c)56  d)72

 

Try again !!

 

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anita you missed out

anita you  missed out negative values

Adding to the two diff cases you have mentioned

For case 1 No of Possibilities = 4!/(2! 2!) =6
For case 2 No of Possibilities = 4!/(3! ) =4
so total number of solutions 6 + 4 = 10

4 = -1 x -1 x  1 x 4      Possibilities = 4!/2! = 12

   = 1 x 1 x -1 x  -4       4!/2! = 12

  = -1 x -1 x -1 x -4      4!/3! = 4

  = 1 x 1 x  -2  x -2     4!/(2! x 2!) =  6

 = -1 x -1 x 2 x 2          6

= -1 x  1 x -2 x  2      24

= -1 x -1 x -2 x  -2   6

Total = 80

 

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NEEL (not verified)
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@RAJORSHI

In the solution of Qn no.4, i coudnt understand how did u find the cyclicity as 2 & 22 & the solution beyond it..could you please explain Rajorshi???????

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hi

Times of India se uthye hue h yeh questions........haina...coming mondy ansrs aa jayenge...check it frm thr.....

 

cheers.....

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ansr of q1

ansr of questn 1(base wala) is 1

 

hint

121a+11b+c=81c+9b+a

 

this will give

60a+b=40c

check fr values

only one value will satisfy

 

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questn 4

hii all

For solving questn no 4, go it by EULER METHOD.

It will be lot easierr....

 

Rt nw in office...il post it 2nite with complete theory of euler and solution to this also.

till thn tke dis mantra:

 

we can solve remainder probs by:

1. by binomial

2. by cyclicity

3.by euler method

4. by manipulations by making the remainder of number 1 or  -1

 

so try solving the questions by above techniques....it vil be helpfull...

 

neone of you cn suggest me a buk from where i can find problems that anita has solved a*b*c*d, some probs like 1/a+1/b+1/c=1/a+b+c....finding no of solutions .....

 

thankssss

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