Answer:
joe=6
Sam=11
Explanation:
lets see...
i explain 1by1
firstly we know that joe is 5 - 3 x Sam
(read the sentences VERY CAREFULLY)
then, we put Sam as math variable "s"
it will be; 5-3 x S

the total of their age is 28

simplify it
it will be 5-S3=28
then you will get 11 right
that will be sam's age
-5 and it will be Joe's age