The average age of instructors at a local college is 55, with a standard deviation of 6 years; the average salary is $37,000 with a standard deviation of $4100. which is more variable?

To solve for the coefficient of variation you will need this formula:
CV = (SD/X) x 100 
Where: CV = Coefficient of Variance
             X = Mean/average
             SD = Standard Deviation

To determine which one is more variable, just get the coefficient of both and compare.
                   AGE                                            SALARY
   
  CV = (6/55) x 100                             CV = (4,100/37,000) x 100
        = 10.90                                             = 11.08

Based on the results, salary is more variable because 10.90<11.08.

Letter c so sorry if i’m wrong ):