self Maths Puzzle

Four different objects 1,2,3,4 are distributed at random in four places marked 1,2,3,4. What is the probability that none of the objects occupy the place corresponding to its number?

Read Solution (Total 1)

considering correct location for four objects 1,2,3,4

required probability that no object at correct position :
total possibilities : 4! = 24 ways

favourable possibilities :
2143,
2413,
2341,
3412,
3142,
3421,
4321,
4123,
4312
ie 9 ways

answer is 9/24=3/8
9 years agoHelpfull: Yes(2) No(0)

self Other Question

A set of cards bearing the number 200-299 is used in a game. if card is drawn at random, what is the probability that it is divisible by?
What is the value of 1×1!+2×2!+3!×3!+............n×n!;
where n! means n factorial or n(n−1)(n−2)...1?