Question:
A seven digit number is formed using digit $3,3,4,4,4,5,5$. The probability, that number so formed is divisible by 2 , is :
Correct Option: , 3
Solution:
$\mathrm{n}(\mathrm{s})=\frac{7 !}{21321}$
$\mathrm{n}(\mathrm{E})=\frac{6 !}{2 ! 2 ! 2 !}$
$\mathrm{P}(\mathbf{E})=\frac{\mathrm{n}(\mathrm{E})}{\mathrm{n}(\mathrm{S})}=\frac{6 !}{7 !} \times \frac{2 ! 312 !}{2 ! 2 ! 2 !}$
$\frac{1}{7} \times 3=\frac{3}{7}$
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