Elitmus
Exam
Numerical Ability
Permutation and Combination
In a theatre all rows have same no. Of . One family buys 10 tickets of first two row. 3 members want to sit in first row and 2 in second row. In how many ways they can be seated.
Read Solution (Total 11)
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- If out of 10 tkts r ticts are from 1st row then 10-r tkts in 2nd row. So ----->rC3 * (10-r)C2
So required Answer----->
3C3 * 7C2 + 4C3 * 6C2 + 5C3 * 5C2 + 6C3 * 4C2 + 7C3 * 3C2 + 8C3 * 2C2 - 8 years agoHelpfull: Yes(30) No(2)
- 10c3x10c2= 5400
- 8 years agoHelpfull: Yes(13) No(5)
- after arranging 3 persn ...in first row .nw we hv 7 sit left in which we can accomodate 2 pesn..inthis way we hv following ways..10c3+7c2
- 8 years agoHelpfull: Yes(6) No(2)
- 10c3 * 7c2 + 10c2 * 8c3
- 8 years agoHelpfull: Yes(4) No(2)
- If out of 10 tkts r ticts are from 1st row then 10-r tkts in 2nd row. So required ans----->rC3 * (10-r)C2
- 8 years agoHelpfull: Yes(3) No(1)
- Out of 10 people choose 3 for first row and arrange them , so number of ways = 10C3 * 3!
Out of remaining 7 people choose 2 people for 2nd row and arrange them, so number of ways = * 7C2 * 2!
Now remaining 5 people can sit any row and can be arranged in 5! ways
So total number of ways = 10C3 * 3! * 7C2 * 2! * 5! - 6 years agoHelpfull: Yes(3) No(0)
- let 3 people n 2 people sit in their rows so ans will be 5c2*5! + 3c3*5!
- 8 years agoHelpfull: Yes(2) No(0)
- since in first row 3 permanent member make 6 possible arrangement and and 2 in the second row make 2 possible arrangement hence we left with 5 people who can sit anywhere so they make 5! =120 possible arrangements so answers will be 120+2+6= 128
- 8 years agoHelpfull: Yes(1) No(0)
- 10c3*3!*7c2*2!*5!+10c2*2!*8c3*3!*5!
- 3 years agoHelpfull: Yes(1) No(0)
- 3 members to sit in 1st row = 10C3
2 members to sit in 2nd row = 10C2
Now, remaining members = 5 can be seated in = 7C5 + 7C4*8C1 + 7C3*8C2 + 7C2*8C3 + 7C1*8C4 + 8C5
Therefore, finally number of ways = 10C3 * 10C2 * {7C5 + 7C4*8C1 + 7C3*8C2 + 7C2*8C3 + 7C1*8C4 + 8C5} - 8 years agoHelpfull: Yes(0) No(2)
- Total number of people = Total number of tickets = 10
Each row has 5 seats (Deduced from the statement.)
3 wants to sit in first row and 2 wants to sit in second row . (So assume that you've told them to sit ).
10 = 5 + 3 + 2.
now,
select two members from remaining 5 members (5C2) and make them sit in first row and arrange them by 5!.
similarly select remaining members (3C3) and make them sit it second row and arrange them by 5!.
so net answer will be
(5C2 * 5!) * (3C3 * 5!).
note that fundamental principal of multipication will be used because if any of the member change it's position its a whole new arrangement. - 4 years agoHelpfull: Yes(0) No(0)
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