How many of them?

How many 5-digit numbers without repetition of digits can be formed using the digits 0, 2, 4, 6, 8?


The answer is 96.

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3 solutions

The five numbers can be arranged in 5 ! 5! times = 120. = 120.

And If zero is in front it is not considered as a five digit number, So keeping zero at first, The remaining four numbers can be arranged by 4 ! = 24. 4! = 24.

Therefore, Number of five digit numbers made using the numbers, = 120 24 = 96 . = 120 - 24 = \color{#D61F06}{\boxed{96}}.

Ashish Menon
May 7, 2016

The number of possibilities of ten-thousandth digit = 4 \color{#20A900}{4} (0 is excluded because then the number does not become a 5-digit number)
The number of possibilities of thousandth digit = 4 \color{#3D99F6}{4} (one digit gone but 0 included)
The number of possibilities of hundredth digit = 3 \color{magenta}{3} (two digits gone)
The number of possibilities of tenth digit = 2 \color{#CEBB00}{2} (three digits gone)
The number of possibilities of units digit = 1 \color{#E81990}{1} (four digits gone)



\therefore Number of 5-digit numbers required = 4 × 4 × 3 × 2 × 1 = 96 \color{#20A900}{4}×\color{#3D99F6}{4}×\color{magenta}{3}×\color{#CEBB00}{2}×\color{#E81990}{1} = \color{#D61F06}{\boxed{96}}

Did the exact same

Aditya Kumar - 5 years ago

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Nice (+1) :)

Ashish Menon - 5 years ago

I did the same analysis. I find it more intuitive than Samara Simha Reddy's analysis.

Mariusz Kula - 3 years, 6 months ago
Vinod Kumar
Aug 11, 2018

Answer is (4!)×4.

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