Answer:
28
Explanation:
To find out how many candidates passed chemistry only, you can use the principle of set theory and the given information.
Let:
A = Set of candidates who passed chemistry.
B = Set of candidates who passed physics.
According to the principle of set theory:
Total candidates who passed at least one subject = Candidates who passed chemistry (A) + Candidates who passed physics (B) - Candidates who passed both subjects
Given information:
Candidates who passed chemistry (A) = 31
Candidates who passed physics (B) = 29
Candidates who failed both subjects = 3
Total candidates (n) = 50
Now, plug in the values:
Total candidates who passed at least one subject = 31 + 29 - 3
Total candidates who passed at least one subject = 57
Now, to find out how many candidates passed chemistry only, subtract the number of candidates who passed both subjects from the total who passed chemistry:
Candidates who passed chemistry only = Candidates who passed chemistry (A) - Candidates who passed both subjects
Candidates who passed chemistry only = 31 - 3
Candidates who passed chemistry only = 28
So, 28 candidates passed chemistry only.