[brajesh.pandey]

Originally Posted by simrat_sandy

let the distances be d1 and d2 that they travel before they meet each other
d1/d2 = (s1*k/s2*k)

d1/s2 =24 => s1*k/s2 =24 ...(1)

d2/s1 = s2*k/s1=54 ....(2)

from 2 k= 54*s1/s2

substituting k in 1

s1^2/s2^2 =4/9
so s1 is 2 and s2 is 3

=>d1= 72; d2= 108

so time taken by A to travel till meeting point
plus from meeting pt to Q
plus from Q till second meeting point

=36+54+36
so I'm getting 126
(hope I've not made any silly mistake typed it on the phone)

Correct
P(0)---------------------------108(m1 a,b)-----------------180(Q)
Meeeting one time = 180/5=36
Now a will travel for 24 min to Q

P(0 b)------------------------------------------------------180(Q a)

then reverse direction and travel for 30 min ie 90 unit left
P(0 b)----------------------90(a)--------------------------180(Q)

So another 90 unit in 18 minutes
P(0)----------36(m2 a,b)-------------------------------------------180(Q)
Total time=18+54+36=108minutes

Please confirm i got this afer seeing the solution...

Added some more points

[shankar.h]

let the total distance be 100. before meeting A travels x m and B (100-x) m.after meeting, A travels (100-x) in 54 min.
therefore, speed of A= (100-x)/54
similarly, speed of B= x/24
time taken before they meet are equal.
x/[(100-x)/54]= (100-x)/(x/24)
x=40 and speed of a=10/9 and dat of b=5/3
in 24 minutes after meeting,B reachas p and by the time A reaches P, it would have travelled for 30 more minutes,i.e 30*5-3=50
distance between the two=50.
time for next meeting=50/[(10/9)+(5/3)]=18
total time=40/(10/9)+54+18=108 min= 1 hr,48 min 1.e 11.48

[crack_2009]

Originally Posted by crack_2009

try it puys:
If X and Y are natural numbers with no common prime factor and Z is the greatest common divisor of (X + Y) and (X^2 + Y^2) then how many values can Z take? --TF

OPTIONS 1)0 2)1 3)2 4)3 5)Cannot be determined

Originally Posted by bishoo123

Was any one able to solve it ? Could not get any clue.

x^2+y^2=(x+y)^2 - 2xy

as both (X + Y) and (X^2 + Y^2) divisible by z
so as -2xy should also divissible by z

2 cases:
1) either 2 is divisible by z
z=1 or 2
2) either x or y divisible by z .either none or both has to be divisible by z to satisfy : (x+y) are divisible by z
x and y are co-prime so z=1

z=1,2
opt 3

[protoplasm]

Originally Posted by uhhh...

math cannot be wrong.. show me a flaw in my method.. thats not a plausible line of reasoning

Can we consider another case ?

Case 3: n odd , n+a-1 even ?

I am saying because i see .. 5 x 100 = 500

n=5 , n+a-1 =100

is that ok ?

[shyam.nair]

what are the last two non zero digits of 25!?

[uhhh...]

Originally Posted by protoplasm

Can we consider another case ?

Case 3: n odd , n+a-1 even ?

I am saying because i see .. 5 x 100 = 500

n=5 , n+a-1 =100

is that ok ?

a wont be odd.. as asked here

Originally Posted by protoplasm

n^2 + (a − 1)n = 500 // a is odd , n is positive integer

Find possible (a,n)

Can you please explain your process.

Thanks

[uhhh...]

Originally Posted by crack_2009

x^2+y^2=(x+y)^2 - 2xy

as both (X + Y) and (X^2 + Y^2) divisible by z
so as -2xy should also divissible by z

2 cases:
1) either 2 is divisible by z
z=1 or 2
2) either x or y divisible by z .either none or both has to be divisible by z to satisfy : (x+y) are divisible by z
x and y are co-prime so z=1

z=1,2
opt 3

what if neither x, nor y is divisible z.. suppose x = p1*k1, y =p2*k2

such that p1*p2 = z

[jaidev_iyer]

In the last summer vacation, Divishth was given an assignment of writing down numbers from 100 to 1000. Despite all his brilliance and intelligence, he gets confused between the digits 6 and 9, and ends up interchanging them.

Q1: How namy numbers did he write correctly in his assignment ?
1. 343
2. 353
3. 448
4. 512
5. None of these

Q2: As a punishment, his teacher asks him to write down the difference btwn the actual number and the number he wrote, for all his incorrectly written numbers. However, he repeats the same mistake while writing the difference btwn the two numbers. How many times did he write the difference incorrectly?
1. 352
2. 176
3. 36
4. 18
5. None of these

[brajesh.pandey]

Originally Posted by jaidev_iyer

In the last summer vacation, Divishth was given an assignment of writing down numbers from 100 to 1000. Despite all his brilliance and intelligence, he gets confused between the digits 6 and 9, and ends up interchanging them.

Q1: How namy numbers did he write correctly in his assignment ?
1. 343
2. 353
3. 448
4. 512
5. None of these

Q2: As a punishment, his teacher asks him to write down the difference btwn the actual number and the number he wrote, for all his incorrectly written numbers. However, he repeats the same mistake while writing the difference btwn the two numbers. How many times did he write the difference incorrectly?
1. 352
2. 176
3. 36
4. 18
5. None of these

q1>The number of numers is 448

[crack_2009]

Originally Posted by uhhh...

what if neither x, nor y is divisible z.. suppose x = p1*k1, y =p2*k2

such that p1*p2 = z

dude if neither of x and y is divisible by z then there xy can't be divisble by z..
hope this ans ur query