The number of students that were absent is; 24
How to find the Probability?
Let the total number of students be x .
The number of students which were absent = ¹/₃x.
Number of students which were present = ²/₃x
Thus;
Number of students who attended math's test = ¹/₂x
Number of students who attended physics test = ¹/₄x
No. of students who attended both tests = 6
A denotes number of students who attended math's test
B denotes number of students who attended physics test
Thus;
n(A) = ¹/₂x
n(B) = ¹/₄x
n(A ∩ B) = 6
n(A∪B) = number of students which were present
Thus;
n(A ∪ B) = n(A) + n(B) − n(A∩B)
²/₃x = ¹/₂x + ¹/₄x − 6
²/₃x = ³/₄x - 6
³/₄x - ²/₃x = 6
x = 72
Thus, number of students that were absent = ¹/₃ * 72
Number of students that were absent = 24
Read more about Probability at; https://brainly.com/question/251701
#SPJ1