@krum said:yaar baye's lagaya hai, @anytomdickandhary sir, aap hi bataein kya hoga __/\__
u still remember that..!!!
@krum said:[ (1/2^5+1/2^6+1/2^7)*3/5 ] / [ (1/2^5+1/2^6+1/2^7)*3/5 + (1/2^8+1/2^9+1/2^10)*2/5]=(21/640) / [(21/640) + (7/2560)]=21*4/(21*4+7)=12/13
" badke bhaiya bhaukaali".........yeh kaun sa teer chod diya........kripya thoda vistaar mein bataiye...
@Harmeet89 said:A student attempts a question paper with 5 true-false questions. He attempts the paper randomly, in no particular order. What is the probability that he gets 4 questions correct out of 5 ?
5C4*(1/2)^4*1/2
5/32
@krum Bhai.. I suppose Baye's would have been involved if it wasn't clarified that Machine-1 is empty. Since Machine-1 has been deemed empty, there is no relation of Machine-1 and Machine-2..??? Kya bolte ho? 
@19rsb said:" badke bhaiya bhaukaali".........yeh kaun sa teer chod diya........kripya thoda vistaar mein bataiye...
@ScareCrow28 said:@krum Bhai.. I suppose Baye's would have been involved if it wasn't clarified that Machine-1 is empty. Since Machine-1 has been deemed empty, there is no relation of Machine-1 and Machine-2..??? Kya bolte ho?
ok,lets be easy on ourselves ; forget that as a random rant ๐ and stick with 3/5 :mg:
@gautam22 said:PFA the ques......bahut bada pad raha hai kuch short batana....totalgadha se liya hai
16km/hr?
@krum said:ok,lets be easy on ourselves ; forget that as a random rant and stick with 3/5
For our relief! ๐ Phewwww...You scared a few souls(including ScareCrow)
@gautam22 said:There are one thousand lockers and one thousand students in the school. The principal asks the first student to go to every locker and open it. Then he has the second student go to every second locker and close it. The third goes to every third locker and, if it is closed, he opens it, and if it is open, he closes it. The fourth student does this to every fourth locker, and so on. After the process is completed with the thousandth student, how many lockers are open?
31??
I suppose the lockers will be open after odd no of operations.
Hence nos that have odd no of factors (Perfect squares) will be open.
There are 31 perfect squares.
@gautam22 said:How it is that when I buy yellow bananas at three shillings a bunch and the same number of red ones at four shillings a bunch I would get two more bunches for the same amount if I divided the money evenly between the yellow and red bananas?
y(x) - 3 rs/bunch
r(x) - 4 rs/bunch
3.5x/3 + 3.5x/4 = 2x+2
=>24.5/12x=2x+2
=>.5/12x=2
=>x=48
so he bought 48 bunches each
r(x) - 4 rs/bunch
3.5x/3 + 3.5x/4 = 2x+2
=>24.5/12x=2x+2
=>.5/12x=2
=>x=48
so he bought 48 bunches each
@ScareCrow28 said:31??I suppose the lockers will be open after odd no of operations.Hence nos that have odd no of factors (Perfect squares) will be open.There are 31 perfect squares.
Please explain first line in some more detail sir... 
@gautam22 said:a 6-digit number. The sum of the digits is 43.And only two of the following three statements about the number are true:(1) it's a square number,(2) it's a cube number, and(3) the number is under 500000.ye nahi ho raha
assuming first digit - 4
43-4 = 39
for it to be a perfect square, it should end with 4,5,6,9 so perfect cube not possible
however, if its perfect cube, it will end with 8, perfect square not possible
for squares, check numbers > 700 , ending with 3 or 7
707 is a fit :splat:
so number is 499849
43-4 = 39
for it to be a perfect square, it should end with 4,5,6,9 so perfect cube not possible
however, if its perfect cube, it will end with 8, perfect square not possible
for squares, check numbers > 700 , ending with 3 or 7
707 is a fit :splat:
so number is 499849
@htomar said:Please explain first line in some more detail sir...
Sir mat bolo yaar.. ๐
See, Initially all the lockers are closed. Now, There is a reversal of initial condition if that locker has been operated.
For Ex:- Locker 1 gets operated only once. Hence It will remain open. Next 2 will get operated twice..Hence It will remain closed. You can see that the nos which have "odd" factors are the ones which will be operated "odd" no of times.
Only perfect squares have odd factors. Hence the answer..
@gautam22 said:approach batana chhoti hai to
Depend on you choti hai ya nai.
Let Speed of D be x times speed of man A.
Let Dn be distance
First meeting
D1/A1=x
D1+A1=1250
Get A1
A1=(1250)(1)/(x+1)
Second meeting distance covered= 1250-2A1
D2+A2=1250-2A1
PUT A1 HERE TO GET
D2+A2=1250*(X-1)/(X+1)
Similarly D3+A3=(1250)[(X-1)/(X+1)]^2
D5+A5=(1250)[(X-1)/X+1)]^4=81*2
x=4;
Dog speed = 4*4=16.
Let Speed of D be x times speed of man A.
Let Dn be distance
First meeting
D1/A1=x
D1+A1=1250
Get A1
A1=(1250)(1)/(x+1)
Second meeting distance covered= 1250-2A1
D2+A2=1250-2A1
PUT A1 HERE TO GET
D2+A2=1250*(X-1)/(X+1)
Similarly D3+A3=(1250)[(X-1)/(X+1)]^2
D5+A5=(1250)[(X-1)/X+1)]^4=81*2
x=4;
Dog speed = 4*4=16.
@gautam22 said:a 6-digit number. The sum of the digits is 43.And only two of the following three statements about the number are true:(1) it's a square number,(2) it's a cube number, and(3) the number is under 500000.ye nahi ho raha
Since the sum of numbers is 43. Therefore, the no is of the form : 9K+7
Now, we can check easily that there exists no number which gives 7 as the remainder after cubing.
Hence the no must be a square( 2 conditions are true)
And it is less than 500000
The squares which satisfy above conditions are from 316^2-708^2
After that we can only use hit and trial ๐ I won't do it
@gautam22 said:a 6-digit number. The sum of the digits is 43.And only two of the following three statements about the number are true:(1) it's a square number,(2) it's a cube number, and(3) the number is under 500000.ye nahi ho raha
Sum of digits = 43
means the number is of form 9k + 7
=> It can not be a perfect cube, as all of the perfect cubes are of form 9k or 9k + 1 or 9k - 1
So, the number is less than 500000 and its a perfect square.
Since it is of form 9k + 7, square root of the number should be of form 9k + 4 or 9k + 5
หลก500000 = 707.xxx
Now, i would call myself lucky as 707 is of form 9k + 4 and 707^2 = 499849 (sum of digits is 43)
Since it is of form 9k + 7, square root of the number should be of form 9k + 4 or 9k + 5, chill sir ye line samajh ni aayi
@gautam22 said:There are one thousand lockers and one thousand students in the school. The principal asks the first student to go to every locker and open it. Then he has the second student go to every second locker and close it. The third goes to every third locker and, if it is closed, he opens it, and if it is open, he closes it. The fourth student does this to every fourth locker, and so on. After the process is completed with the thousandth student, how many lockers are open?
is it 31 ? ( nos. wid perfect squres )
PS: chill Sir \_____o & ___/\____
@sumit99 said:Since it is of form 9k + 7, square root of the number should be of form 9k + 4 or 9k + 5, chill sir ye line samajh ni aayi
Let N= 9k+4
N^2 = 81k^2 + 8*9k + 9 +7
Hence remainder is 7
Similarly for 9k+5; N^2mod9 =7
For other nos It's not of the form 9k+7..
Que:-
One day I stared from A to B at exactly 12 noon.My friend started from B to A at exactly 2:00 pm.We met at 5 Past 4 and reached our destinations exactly at the same time.What time was it?
Please explain the solution...