Final answer:
The worker's error was dividing by 2 instead of dividing 2 by 1.
Step-by-step explanation:
The worker's error was option 2) The worker divided by 2 instead of dividing 2 by .
To understand the error, we need to set up the problem correctly. The worker can install 2 windows in 1 day, so the rate of installation is 2 windows per 1 day. However, the worker mistakenly divided by 2 instead of dividing 2 by 1. This error resulted in the incorrect rate of window installation.
To fix the error, the worker should have divided 2 by 1, which would give the correct rate of 2 windows per 1 day.