Latest TCS Aptitude Question SOLUTION: A person have 2 types of pair of socks. Total 10 pairs exists in a bag. If he selected 3 socks from bag at random, find the probability of selecting atleast one pair of socks.

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A person have 2 types of pair of socks. Total 10 pairs exists in a bag. If he selected 3 socks from bag at random, find the probability of selecting atleast one pair of socks.

Asked In TCS saumya shukla (9 years ago)

Unsolved Read Solution (19)

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Read Solution (19) :

shrey  (9 years ago)

probability=1 because in 3 selection always one pair exist

Is this solution Helpfull? Yes (44) | No (35)  

Bhargavi Mullapudi  (9 years ago)

10 pairs (i.e, 10L & 10R)
n(s)= 20C3
selecting 3 socks, atleast one pair of socks is 2*10C2*10C1
probability = 2*10C2*10C1/20C3 = 15/19

Is this solution Helpfull? Yes (26) | No (8)  

tanushri  (9 years ago)

10 pairs means 10 L and 10 R
SO, ((10C1*10C2)+(10C2*10C1))/20C3

Is this solution Helpfull? Yes (17) | No (2)  

chandana priya  (9 years ago)

plz declare which is crt answr at last

Is this solution Helpfull? Yes (5) | No   

gorijala swathi  (9 years ago)

probability 1

Is this solution Helpfull? Yes (4) | No (4)  

anand vijay  (9 years ago)

there are 5 pairs each of two different types of socks.
let we have type a and type b socks
all of the three sock from type a or type b
1 sock from type a and 2 sock from type b
2 sock from type a and 1 sock from type b
in all of these three case there is one pair of sock
hence,probability=1

Is this solution Helpfull? Yes (3) | No (7)  

Kajal Karande  (9 years ago)

Given that there are only 2 types of socks. So while selecting 3 socks we can have (2 same and 1 different)
Therefore we get 100% i. e. probability 1

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

shakshijain  (9 years ago)

probability is 1,
because it is given that two types of pair exists that means if 5 pair is of one colour than another 5 will be of different colour . therefore by selecting 3 socks it is confined that one pair always exists . may be it is of ano coclour or of other.

Is this solution Helpfull? Yes (3) | No (1)  

ramya sree  (9 years ago)

20c1*1c1*18c1/20c3=3/19

Is this solution Helpfull? Yes (2) | No (9)  

Satish Gampala  (9 years ago)

15/19 is correct answer...

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

Partha Ghosh  (9 years ago)

if a person has 2 pairs of socks. then after he selected randomly 3 socks there should be one pairs of socks this is certain event so probability=1 to find atleast one pair of socks

Is this solution Helpfull? Yes (2) | No   

sampath  (9 years ago)

1
AS ALL SHOCKS ARE SAME PROBSBILITIY IS 1

Is this solution Helpfull? Yes (1) | No (6)  

Ritika Jain  (9 years ago)

ans. should be 3/19

since 3 socks are chosen therefore 1 pair is for sure chosen among them..
to choose that one pair we have: 10C1.
from the left 18 socks we have to now choose 1 more sock therefore: 18C1.
this selection of 3 socks is done from a total of 20 socks therefore: 20C3.

hence the expression becomes:

(10C1*18C1)/(20C3)= 3/19

Is this solution Helpfull? Yes (1) | No (5)  

kakarla venugopal  (9 years ago)

2*10c2*10c1/20c3=15/19

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

Pratik sharma  (9 years ago)

answer is :1

Is this solution Helpfull? Yes (1) | No (2)  

Ritu Jha  (9 years ago)

[10c1 * 18c1]/20c3

Is this solution Helpfull? Yes | No (3)  

srikanth  (9 years ago)

(10c1/20c1)*(10c1/19c1)*(9c1/18c1)==5/38

Is this solution Helpfull? Yes | No (1)  

parth agrawal  (8 years ago)

7/24
if he takes out 7 shocks out of 10 then he had definitely 1 pair of shocks so,
7c3/10c3

Is this solution Helpfull? Yes | No   

Richa  (8 years ago)

Since there are 10 pair means 20 socks nd he choose 3.. For atleast 1 we have 1-(20*18*16/20 p 3)

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