Postmen
Probability
Level
3
You have 6 friends to invite on your birthday party. You have three servants who can send the invitation cards. Find the number of of ways in which you can send them the invitation cards.
It doesn't matter in which order the invitations are being sent (by time)
The answer is 729.
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1 solution
A card can be send to any one friend by any one of the three servants.
Let us take the tasks of sending cards to six friends as T1, T2, T3, T4, T5 and T6.
Each of the tasks can be completed in three distinct ways according to the number of servants to carry the cards.
Thus, by the multiplication principle of counting the tasks T1,T2,T3,T4,T5,T6 can be performed in
3 × 3 × 3 × 3 × 3 × 3 = 7 2 9 ways.