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A bag contains 12 red balls and 6 white balls. Six balls are drawn one by one without replacement of which at least 4 balls are white. Find the probability that in the next two draws exactly one white ball is drawn.. ans in nCr

Please explain it in detail! !!!!!!

Thanks in advance

In a class of 10 students there are 3 girls A B C. In how many different ways can they be arranged in a row such that no two of the the girls are consecutive. ....

My two point of views..

1) there are 8 gaps in between 7 boys. So ans is 8P3 × 7! = 42×8!(Gap Method )

2) 10! - 8!×3! = 84×8! ( String Method)

Please tell me why the error is coming in strong method..... please elaborate it I shall be thankful to you....

And ans is 42×7!

I want to know that whether one can give IIT jee examination next year after getting admission into the engineering college ......

If |x^2|<4 then x lies b/t ?????...

Please explain the solution.....

A small block of mass m is kept on a rough inclined surface of inclination ∆ in an elevator. The elevator goes up with a uniform velocity v and the block doesn't slide on the wedge. The work done by the force of friction on the block in time t will be....

My answer 0 as the displacement is 0

Real answer mgvt(sin^2∆).... How???????

Please explain...

While solving a few problems of maths I got stuck up on one concept i.e

If. x^2 lies btw [1,0] then x lies btw what to what..... Send your answer with explanation....

PLEASE find the argument of iota^iota ..... my answer is π/2 but the book's answer is 0... tell me where am i wrong...

tan(y/x)=(iota^iota/0) =∞ AND THAT IS EQUAL TO tan(π/2) and hence the arg(z)=π/2

1+ 1+x +(1+x+x^2) +(1+x+x^2+x^3) +-----+ n terms......

Lt x---->0 [cos(sinx) - cosx]/x^4

Please show me the way to apply the chain rule step by step and help me to find the derivative of. logcos^m(x) wrt to x....... Help me fast.....

A vector a is rotated through an angle θ, what is the magnitude of change in the vector???

Ans is 2a sin(θ/2)........

Solve this.......

find the no. of electrons in chromium which have orbital angular momentum equal to h/√2 π

Ans. 12

1) In a hypothetical H-atom, the mass of electron and charge is double of what we consider, the total energy of electron in first orbit of such hupothetical H- Atom is

Ans is -13.6 X 32 eV

Hey guys Please tell me the book name fast........

The relation b/t time t and distance x is

t= ax^2 + bx

where a & b are the constants..............

The retardation is

I don't find any difficulty to differentiate first time to find the velocity but when it comes to differentiate again to find acc., I don't get the point.. So please help me to differentiate such kind of relations.......

Please explain me about wave function....... But please maintain the level of class XI only........

What is the common difference between.....

1) M.L Khanna Objective mathematics, M.L. Khanna IIT Mathematics and M.L Khanna New Pattern Mathematics for IIT-JEE

If SinA= 1√10 and SinB= 1/√5, then Sin(A+B) =

Pie/4

Pie

Pie/2

2pie/3

Ans is Pie/4 (45 degree)

Answer quickly and get golden 10 pts.........

Be3+ and a proton are accelerated by the same potential, their de Broglie wavelengths have the ratio.(assume mass of proton = mass of neutron)

Ans is 1:3√3

Please explain it in detail...............