Wouldn't it be answer b)?
The total number of employees are 80. I know that because 25 is quarter of 100 and if 20 employees are 25%, all I need to do is 20*4 which is 80. Hope this helped!
Your answer would be 3.4
Anything under 5 it stays the same and anything over 5 it goes up one
Yes it is congruent to5x-1