Explanation:
[tex]\sf Average \ Result : \dfrac{sum \ of \ value \ of \ scores}{sum \ of \ weight}[/tex]
Workout:
[tex]\sf For \ candidate \ X = \dfrac{70 \ \cdot \ 4 \ + 78 \ \cdot \ 3 \ + 70 \ \cdot \ 4 }{4 + 3 + 4} = 72.18 \ \ average \ score[/tex]
[tex]\sf For \ candidate \ Y = \dfrac{89 \ \cdot \ 4 \ + 83 \ \cdot \ 3 \ + 89 \ \cdot \ 4 }{4 + 3 + 4} = 87.36 \ \ average \ score[/tex]
[tex]\sf For \ candidate \ Z = \dfrac{85 \ \cdot \ 4 \ + 89 \ \cdot \ 3 \ + 85 \ \cdot \ 4 }{4 + 3 + 4} = 86.09 \ \ average \ score[/tex]
Conclusion:
Among all of them, candidate Y has the best average score of about 87.36 whereas candidate Z has second best score of 86.09 average score and candidate X has the least average score of 72.18.
Candidate Y is the appropriate candidate for this position on the criteria.