Amath teacher gave two quizzes and wanted to find out what percent of those who passed the first test also passed the second test. what would she have to do?

Count how many student passed the first test
Then count how many of those passed the second
Divide the number of students that passed the second by the number of students that passed the first
This will give you the percentage

Example: she gives the first test to the class only 10 pass
She gives out a second test and out of the 10 that passed before 6 passed the second test

So you would divide 6 by 10 getting a percentage of 60%

40 & 50 in the right corner are the complementary angles as when placed in a sum (added together) they make 90°