TCS
Company
Numerical Ability
Permutation and Combination
Seven different objects must be decided among 3 persons. In how many ways this can be done if at least one of them gets exactly one object???
Read Solution (Total 21)
-
- n-1c r-1 =6c2=15
- 9 years agoHelpfull: Yes(15) No(7)
- Division of m+n+p objects into three groups is given by (m+n+p)/(m!×n!×p!)
so, according to question at least one gets only one object this can be done in (1,1,5),(1,2,4),(1,3,3) ways.
required number of ways= (7!/(1!*1!*5!))*(1/2!) + (7!/(1!*3!*3!))*(1/2!) + (7!/(1!*2!*4!)) = 196 - 9 years agoHelpfull: Yes(11) No(3)
- (1) suppose only 1 person gets 1 object.
so, the other two get either (0,6) or (2,4) or (3,3) objects.
so, no. of ways of partitioning the remaining 6 objects into each such group = 1, 15, 20 respectively
req no. of ways this can happen = 7*3*(1+15+20)*2
(2) now suppose only 2 persons get 1 object each
so, the third must get remaining 5
req no. of ways this is possible = 3*21
add up the nos. - 9 years agoHelpfull: Yes(2) No(2)
- (7!/(1!*1!*5!))*(1/2!) + (7!/(1!*3!*3!))*(1/2!) + (7!/(1!*2!*4!)) = 196
- 9 years agoHelpfull: Yes(2) No(0)
- Answer must be like in that way...
They have already said different object so first take a,b,c three people ,a get 1 object in 7 way .and remaining 6 obj can be divided as 6c2 way .as they diffrnt ..so thats 7x6c2=105 ways..and this can be happened three way.. so ans in 315 . - 9 years agoHelpfull: Yes(1) No(2)
- Division of m+n+p objects into three groups is given by (m+n+p)!m!*n!*p!
But 7=1+3+3 or 1+2+4 or 1+1+5
so the number of ways are (7!) 1! * 3!*3!*12!+(7)!1!2!4!+(7)!1!*1!*5!*12!=70+105+21=196
so the answer is 196 - 9 years agoHelpfull: Yes(1) No(1)
- formula for this is( m+n+p)!/m!n!p!
so 7!/3!=140 ways
- 9 years agoHelpfull: Yes(0) No(4)
- 7 different objects must be decided among 3 persons.
so,no of ways to get by exactly one person,exactly one object = 7C3 -1 - 9 years agoHelpfull: Yes(0) No(1)
- 7c3=7*6*5*4*3/1*2*3
=420 - 9 years agoHelpfull: Yes(0) No(1)
- 6 items can be divided into 6c2=15ways
and anyone gets one item
so total no ways =15*3=45
- 9 years agoHelpfull: Yes(0) No(1)
- 7p3 is the right answer
- 9 years agoHelpfull: Yes(0) No(2)
- 7c3 - 3 - 0 = 7c3 - 3
7c3 = 7 different objects decided among 3 persons.
3 = ways in which 1 object can be given to 2 men.
0 = ways in which 1 object can be given to 3 men
So the remaining are the ways in only 1 man get 1 object - 9 years agoHelpfull: Yes(0) No(0)
- (1) suppose only 1 person gets 1 object.
so, the other two get either (0,6) or (2,4) or (3,3) objects.
so, no. of ways of partitioning the remaining 6 objects into each such group = 1, 15, 20 respectively
req no. of ways this can happen = 7*3*(1+15+20)*2
(2) now suppose only 2 persons get 1 object each
so, the third must get remaining 5
req no. of ways this is possible = 3*21
- 9 years agoHelpfull: Yes(0) No(1)
- lets take it like this _ _ _ .3 people have to get from 7 objects. In question it has stated that one has to get exactly one object so 1st person gets one then remaining 2 person has to get from 6 objects
possibilities
2nd person 6
3rd person 5
so 1*60*5 = 30
Ans:30 - 9 years agoHelpfull: Yes(0) No(0)
- The objects can be divided into three groups that are (1,1,5) or (2,4,1) or (3,3,1) as atlas one person should get 1 object.
so number of ways can be [(7C1*6C1*5C5)/2!]+(7C2*5C4*1C1)+[(7C3*4C3*1C1)/2!]=196 - 9 years agoHelpfull: Yes(0) No(0)
- case1: * * *
1 object for one person and remaining 6 objects for 2 persons=6c2=15
three cases are possible so 3*15=45
case2: for 2 persons each one object then fr one person 5 objects
3 cases are possible so 3*5=15
hence 15+45=60 - 9 years agoHelpfull: Yes(0) No(0)
- there 7 objects
so 1 give to each
4 remains
as per product and sum rule 3*(4+3+2+1)=3*10=30
ans:30 - 9 years agoHelpfull: Yes(0) No(0)
- there are 3 possible dist. scenario. (1,1,5),(1,2,4),(1,3,3)
(1,1,5)
since seven objects are different, not identical, thus no of ways of dist.ing them = (7C1+6C1+5C5)*(3!/2!)=126
similarly,
for(1,3,3)
(7C1*6C3*3C3)*(3!/2!)=420
for(1,2,4)
(7C1*6C2*4C4)*(3!)=630
hence total ways=(630+420+126)=1176
- 9 years agoHelpfull: Yes(0) No(0)
- Answer is 15
because
x+y+z=7
question says at least one
(1,1,5)=this can be done in 3!/2!=3 or(+)
(2,2,3)=this can be done in 3!/2!=3 or(+)
(1,3,3)=this can be done in 3!/2!=3 or(+)
(1,2,4)=this can be done in 3! = 6
so finally sum is 15
:) - 9 years agoHelpfull: Yes(0) No(0)
- 1 2 4 3! =6
1 3 3 3!/2=3
1 1 5 3!/2=3
6+3+3=12
- 9 years agoHelpfull: Yes(0) No(0)
- ans is 18 ..because atliest one of them get one object!!!
- 8 years agoHelpfull: Yes(0) No(0)
TCS Other Question