Latest Infosys Aptitude Question SOLUTION: A Jar contains 18 balls. 3 blue balls are removed from the jar and not replaced.Now the probability of getting a blue ball is 1/5 then how many blue balls jar contains initially?

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A Jar contains 18 balls. 3 blue balls are removed from the jar and not replaced.Now the probability of getting a blue ball is 1/5 then how many blue balls jar contains initially?

Asked In Infosys NagaRaj SV (10 years ago)

Solved krishna Read Solution (14)

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Read Solution (14) :

krishna  (10 years ago)

x/15 = 1/5
x =3
3+3(removed 3 blue balls) = 6

Is this solution Helpfull? Yes (67) | No   

Arijit Roy  (10 years ago)

Let initially no. of blue balls are x.

so, initially probability of getting 1 blue ball = (x) combination 1 = x
after remove 3 blue balls no. of blue balls in the jar = x-3
now the probability of getting 1 blue ball = (x-3) combination 1 = x-3
as, x-3 = 1/5 , x = 3.
so, initially no. of blue balls in the jar = 3 + 3 = 6. (because after remove 3 blue balls we get 3 blue balls in the jar.)

Is this solution Helpfull? Yes (10) | No (7)  

NIRAJ BARNWAL  (10 years ago)

Let left blue ball is x,then a/c
xc1/15c1=1/5
thus, x=3
so total no. of blue ball is 3+3=6.

Is this solution Helpfull? Yes (10) | No (1)  

Pintu Sharma  (10 years ago)

6 blue balls.

Is this solution Helpfull? Yes (3) | No   

Aftab Alam  (10 years ago)

more than 3 and less than 6

Is this solution Helpfull? Yes (2) | No   

souvik mukherjee  (9 years ago)

initially blue balls=x
3 blue balls are removed
so, x-3/15=1/5
x-3=3
x=6(ans)

Is this solution Helpfull? Yes (2) | No   

FAISAL SK  (9 years ago)

after removing 3 ball remaining ball=15
p(a)=n(a)/n(s)=1/5; ow n(s)=15
n(a)=3:
so the total blue ball=3+3=6

Is this solution Helpfull? Yes (1) | No   

lalithyakotareddy  (5 years ago)

let the total number of blue balls = x.
now, out of 18 balls, three blue balls are removed, so the number of balls will be 18-3 = 15

we have (x-3)/15 = 1/5 [the probability of blue balls that are presented in the jar]
==> x-3 = 3
x=6
the number of blue balls the jar contained initially = 6

Is this solution Helpfull? Yes (1) | No   

Saga Sri Lalitha Mrudumouni  (10 years ago)

8 blue balls

Is this solution Helpfull? Yes | No (8)  

KONDURU MAHESH  (10 years ago)

6
at first 3blue balls are removed then remaining balls=18-3=15
p=xc1/15c1=1/5;
x=3

Is this solution Helpfull? Yes | No   

savita  (9 years ago)

x/15=1/5
x=3

Is this solution Helpfull? Yes | No (1)  

Subrata Sarkar  (9 years ago)

6 blue balls

Is this solution Helpfull? Yes | No (1)  

Chirag Ranjan Lahiri  (9 years ago)

x/15 = 1/5
x =3
3+3 = 6

Is this solution Helpfull? Yes | No   

BRINDHA P  (8 years ago)

Here are not mentioned fully blue balls

Is this solution Helpfull? Yes | No (1)  

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