Answer: 12
Step-by-step explanation:
Given : The total number digits given : 4
Since repetition is not allowed then to find the number of different positive integers of 2 digits each can be made with the digits 2, 4, 5, and 8 we use permutations.
We know that the permutation of n things taking m at a time is given by :-
[tex]^nP_m=\dfrac{n!}{(n-m)!}[/tex]
Similarly, the number of permutations of 4 things taking 2 at a time is given by :-
[tex]^4P_2=\dfrac{4!}{(4-2)!}\\\\=\dfrac{4\times3\times2!}{2!}=12[/tex]
Hence, the required number of different positive integers = 12.
