Latest IBM Aptitude Question SOLUTION: A bag contains 2 red, 3 green and 2 blue balls. Two balls are drawn at random. What is the probability that none of the balls drawn is blue? Options 1) 10/21 2) 11/21 3) 2/7 4)

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(#M40005184) IBM Numerical Ability question Keep an EYE

A bag contains 2 red, 3 green and 2 blue balls. Two balls are drawn at random. What is the probability that none of the balls drawn is blue?
Options
1) 10/21
2) 11/21
3) 2/7
4) 5/7

Asked In IBM srilatha (12 years ago)

Solved Dr.Dipin Singh Read Solution (9)

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Read Solution (9) :

Dr.Dipin Singh  (12 years ago)

In 60 min , min hand moves by 360 deg and hour hand moves by 30 deg.

After 60 min diff in angles = 360-30 = 330 deg.

For meeting again, diff of angles should be 360 deg.

Angle will be 360 deg after 360*60/330 = 720/11 min from 12O'clock
i.e. after 65 5/11 mins

Is this solution Helpfull? Yes (21) | No (5)  

hari singh bhadoriya  (9 years ago)

total no of possible event=n(E)=7c2=21
ball is drawn either red or blue then possible outcomes =n(p)=(2c1*3c1+2c2+3c2)=10
probability p(E)=n(p)/n(E)=10/21ans.

Is this solution Helpfull? Yes (9) | No   

Shivani Shishodia  (7 years ago)

Total number of balls=2+3+2=7. Number of ways of drawing 2balls out of 7=7C2=21. Number of ways of drawing 2(blue) ball out of(2+3) balls. =5C2=10. Therefore, none of ball drawn blue=10/21

Is this solution Helpfull? Yes (5) | No   

Dr.Dipin Singh  (12 years ago)

@ sanjana,
I do not think that such qn will be asked here.
In that case, the two clocks are always matching even after 1 millisecond.

But your observation is correct. I think the question is incomplete.

Is this solution Helpfull? Yes (3) | No (5)  

Sanjana Patnaik  (12 years ago)

It is not about the two hands of the clock
It is about two clocks. So they meet the next second again

Is this solution Helpfull? Yes (2) | No (14)  

Macha Devendher  (9 years ago)

M=minuts,H=Hours
our formula for calculating angle between any hands i.e (11/2)*M-30*H
now both hands are meet together means 0degree or 360 degree
so
given H=12
(11/2)*M-30*12=0
M=720/11 i.e 65 5/11 minuts after means 1 hr 26/5 minuts

Is this solution Helpfull? Yes (2) | No   

puja pradhan  (7 years ago)

As none of the ball is blue so, 2 red and 3 green will be considered
so tot =5ball and no. of ball needed to be selected is 2 from 5
so (5c2) / 7c2(tot)
=10/21

Is this solution Helpfull? Yes (1) | No   

lakshmi  (7 years ago)

total balls 7c2=21 select two balls none of them is blue so 2c1*3c1+2c2*3c0+3c2*2c0=15 finally 15/21=5/7

Is this solution Helpfull? Yes (1) | No   

Maheshwari  (5 years ago)

Ans:11/21
Total- none
1-5c2/7c2

Is this solution Helpfull? Yes | No (1)  

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