If a 4 digit number is formed at random without repetition using the digits 0, 1, 2, 3, 4, then the probability that the number thus formed is even is
If a 4 digit number is formed at random without repetition using the digits 0, 1, 2, 3, 4, then the probability that the number thus formed is even is
There are 4 places: _ _ _ _
As repetition is not allowed,
Thousands place cannot have 0, so there are only 4 choices for that position.
Hundreds placeĀ can have all other remainingĀ 4 choices for that position.
Tens placeĀ can have all other remaining 3 choices for that position.
Units places can have only remaining 2 choices
So, through fundamental process of counting
No. of numbers possible = 4 x 4 x3 x 2 =96
For even nos. units place should be either 2 or 4 or 0
In a similar way of counting lets first fix 2 or 4Ā
So for thousands placeĀ 3 options are remaining (except 0).
Hundreds place can have all other remaining 3 choices for that position.
Tens place can have all other remaining 2 choices for that position.
Units places can have only remaining 2 choices. (2 or 4)
No. of numbers possible = 3 x3 x 2 x 2 = 36
In a similar way of counting lets first fix 0
So for thousands place 4 options are remaining (except 0).
Hundreds place can have all other remaining 3 choices for that position.
Tens place can have all other remaining 2 choices for that position.
Units places can have only remaining 1 choices. (only 0)
No. of numbers possible = 4 x 3 x 2 x 1= 24
Total Even nos. 36+24 = 60
Probability = 60/96 = 5/8 Answer
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