Chapter 11 Data Analysis and Statistics - 11.2 Apply Transformations to Data - 11.2 Exercises - Problem Solving - Page 755: 25

See below.

There are $15$ supervisors; thus the total salary of people will increase by $15\cdot5000=75000$, which on average for the $100$ employees is an increase of $750$. Since the supervisors earned above the median before the increase, the increase won't affect the median.