If you add the measures of combined angles to find their sum, and then measure the larger angle with a protractor and get a different answer, what possible errors could you have made?

Awoman has 14 different shirts: 10 white shirts and 4 red shirts. if she randomly chooses 2 shirts to take with her on vacation, then what is the probability that she will choose two white shirts? show your answer in fraction and percent, round to the nearest whole percent.