Tim's phone service charges $25.08 plus an additional $0.22 for each text message sent per month. if tim's phone bill was $30.58, which equation could be used to find how many text messages, x, tim sent last month?

3 workers

if 12 workers can do a piece of work in 20 days, then one person can do it in 240 days. 240/16 is 15. That is the number of workers that you need in total to it in 16 days. Since the question ask how many more workers,
15 - 12 = 3 more workers.