In a math class with 19 students, a test was given the same day that an assignment was due. There were 12 students who passed the test and 13 students who completed the assignment. There were 4 students who failed the test and also did not complete the assignment. What is the probability that a student who completed the assignment passed the test?Answer:
Q. In a math class with 19 students, a test was given the same day that an assignment was due. There were 12 students who passed the test and 13 students who completed the assignment. There were 4 students who failed the test and also did not complete the assignment. What is the probability that a student who completed the assignment passed the test?Answer:
Total Students Count: First, let's determine the total number of students who either passed the test or completed the assignment, or both. We know that 4 students neither passed the test nor completed the assignment. Since there are 19 students in total, this means that 19−4=15 students either passed the test, completed the assignment, or did both.
Find Students Both Passed and Completed: Next, we need to find out how many students both passed the test and completed the assignment. We can use the principle of inclusion-exclusion for this. The formula is:Number who did both =(Number who passed the test)+(Number who completed the assignment)−(Total number who passed the test or completed the assignment or both)
Calculate Number Who Did Both: Now we plug in the numbers we have:Number who did both =12+13−15
Calculate Probability: Calculating the number who did both gives us:Number who did both = 25−15Number who did both = 10So, there are 10 students who both passed the test and completed the assignment.
Calculate Probability: The probability that a student who completed the assignment passed the test is the number of students who did both divided by the number of students who completed the assignment.Probability = Number who completed the assignmentNumber who did both
Final Probability: Plugging in the numbers we have:Probability = 1310
Final Probability: Plugging in the numbers we have:Probability = 1310The fraction1310 cannot be simplified further, so this is the final probability.
More problems from Probability of independent and dependent events