Answer:
Workers in San Diego = 260 workers
Explanation:
Total workers = 480
Number of offices = 3
In each office in different cities
New york = 90 workers
Denver = 130 workers
San Diego = x workers
Find x
Total number of workers = workers in New York + workers in Denver + workers in San Diego
480 = 90 + 130 + x
480 = 220 + x
480 - 220 = x
260 = x
x = 260 workers
Workers in San Diego = 260 workers