Stephanie-is-solving-the-probability-problem-below-incorrectly-algebra-homework-help

Stephanie is solving the probability problem below incorrectly. In which line does she first make an error? Find and correct the error in this line.

Brittany plans to take Pre-Calculus, English 12, Physics, Physical Education, Economics, and Anthropology in her senior year. She hopes to have Pre-Calculus and Physics in the morning. What is the probability that her first two classes will be Pre-Calculus or Physics