kavish2000 Says

my guess is the answer is POD=36 degree..its a stupid logic..but whast the answer?

After a long time A sense of nostalgia and a sens of failure in cat

Find the highest natural number N, less than 400, such that N can be written as sum of consecutive natural numbers in 11 ways but cannot be written as sum of 11 consecutive natural numbers.
According to the rule of reflection, the angle of incidence (angle that the incident ray makes with the normal) is equal to the angle of reflection (angle that the reflected ray makes with the normal). A ray of light, originating perpendicularly at point P on the diameter AB of a semicircular mirror, is reflected at two points, D and E, on the mirror before passing through point B. What is the measure of angle POD?
P.S: don't the ans.

Q1)9 boxes are arranged in a 3*3 form...
now 4 similar things are to be placed in these 9 boxes such that...there is atleast on item in each row and in each column...In how many ways can this be done
Q3) Let Sm denotes the sum of the digits of first m natural numbers...For which of the following values of m will Sm be divisible by 25...
a)304 b)310 c)330 d)297

the question is a+b+c = 4
so isnt the ans 6C2 = 15 ways??
out of this one is not possible... 004
so totally 14 ways..

Hi puys

Some questions from my end . As usual methodology is more welcomed than the answer .


4. Given that P and Q are the roots of teh equation Ax^2 -4x + 1 =0 and R and S are the roots of the equation Bx^2 -6x +1 =0 . What is teh value of A so that P,Q,R, and S are in HP ?

a)1 b)2 c)3 d)4


p+q= 4/a
pq=1/a
r+s=6/b
rs=1/b

lt p=1/x q=1/y r=1/z s=1/w in hp
xyzw are in ap

1/x+1/y=4/a
x+y/xy=4/a
1/xy=1/a
x+y=4
similarly z+w=6
x+y+z+w=10
only possible option 1234
x=1 y3 z=2 w=4
4/3=4/a
so ...a=3... option 3

can u explain why there is no other solution possible for
x+y+z+w=10??

can we not take x=2,y=2 and z=1,w=5???

Is the ans (3) 222??
approach: N%27...
Is that right bro???

@Sachin.. thanks a lot for the qns buddy... Really challenging and gud ones. Here are my first set of solutions,


1. The street of a city are arranged like the lines of a chessboard , there are m street running north and south and n east and west . Find the no. ways in which a man can travel from N.W to the S.E corner, going by the shortest possible distance.
16!/(8!*8!) = 16C8

2. How many different arrangement can be made out of the letters in the ex-pression a^3b^2c^4 when written at full length?
Ans. 1260. ( I am getting 10!/4)

3. How many 7-digit numbers exist which are divisible by 9 and whose last but one digit is 5?
Find the solutions for, a+b+c+d+e+f = 13
a+b+c+d+e+f = 22
a+b+c+d+e+f = 31
a+b+c+d+e+f = 40
a+b+c+d+e+f = 54
Where 1<=a<=9 0<=b,c,d,e,f<=9


4. You continue flipping a coin until the number of heads equals the number of tails. I then award you prize money equal to the number of flips you conducted .How much are you willing to pay me to play this game?
Actually I don't gamble...

still thinking for some breakthrough


5. Consider those points in 3-space whose three coordinates are all nonnegative integers, not greater than n. Determine the number of straight lines that pass through n of these points.
Need to find the no of points,
For x=0, y and z can have 0-N values, so (N+1)^2 ways
For x=1. Similalrly (N+1)^2 ways
..for x=n .. Similalrly (N+1)^2 ways
So totally, (N+1)^2 * (N+1)(N+2)/2 = some Y
So the total lines is Yc2.. phew!!!

Hope the ans are correct..