Permutation & Combination

On 3 different days a man has to drive to a railway station and he has 5 conveyances; in how many ways can he make the 3 journeys ?

I have done:

5C3.3! + 5C1.4C13!2! + 5C1 = 125

The ans is right but i think somewhere i have not followed the rule. Where have i gone wrong ?

3 Answers

62
Lokesh Verma ·

where did you get 5 from!!??

The way i think the answer should be is 3x3x3=27!

1
Bicchuram Aveek ·

Sir it's a quest. from Hall and Knight :

I've taken 3 cases :

1 : He takes 1 carriage for 3 days.
2 : 1 carriage for 2 days and another for 3rd day.
3 : 3 carriages for 3 days.

62
Lokesh Verma ·

ok.. so you have edited the question [3]

for what you have done, the method and the answer is correct

the only thing is that the same could be done in a much easier way... 5x5x5 = 125

5 ways to chose a carrier each day :)

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