Answer:
I will answer in English.
Here, we want to find all the 3-digit multiples of 5, that can be formed with the digits:
a) 5, 7, and 8. (i suppose that we can not repeat the digits)
First, we know that all the multiples of 5 end with a 5 or a 0, then the possible ones here are:
875
785
(the five must always be at the end)
b) 0, 3, and 5.
Now we have two options, if the 5 is at the end, we have:
305
(035 is not an option, because is a 2-digit number).
if 0 is at the end, we have:
350
530
