Performance rating calculation FF

Summary

Performance rating calculationFF

Content

we need to create Performance rating calculation Fast formula,

we need to calculate the overall performance rating based on goal rating and goal weightage.

for example as below 

Goal      Employee rating         Weightage               Overall goal rating

Goal1      3                                    20%                           0.6

Goal2      2                                     30%                          0.6

Goal3       3                                    50%                         1.5

Overall rating to calculated ad 2.7

Can any one help on this how to create Fast formula for above requirement