In a class of 100 students, 55 students have passed in Mathematics and...
Let A be the set of students who have passed in Mathematics, and B be the set of students who have passed in Physics.
We are given that |A| = 55 and |B| = 67, where |A| and |B| represent the number of students in sets A and B, respectively.
We are also given that there are 100 students in total. We need to find the number of students who have passed in Physics only, which means we need to find |B - A|.
First, let's find the number of students who have passed in both Mathematics and Physics, which can be represented by |A ∩ B|.
Using the principle of inclusion-exclusion, we have:
|A ∪ B| = |A| + |B| - |A ∩ B|
Since there are 100 students in total, we can say that |A ∪ B| = 100.
Now, we can find |A ∩ B|:
100 = 55 + 67 - |A ∩ B|
100 = 122 - |A ∩ B|
|A ∩ B| = 22
Now, we can find the number of students who have passed in Physics only, which is |B - A|:
|B - A| = |B| - |A ∩ B|
|B - A| = 67 - 22
|B - A| = 45
so, the correct answer is 45.
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In a class of 100 students, 55 students have passed in Mathematics and...
Solution:
Given, there are 100 students in a class, out of which 55 have passed in Mathematics and 67 have passed in Physics.
Let A be the set of students who have passed in Mathematics and B be the set of students who have passed in Physics.
Then, we have,
n(A) = 55
n(B) = 67
Now, we need to find the number of students who have passed in Physics only, i.e., the number of students in the set B but not in the set A.
Let x be the number of students who have passed in both Mathematics and Physics, i.e., the number of students in the intersection of sets A and B.
Then, we have,
n(A ∩ B) = x
Using the formula for the number of elements in a union of two sets, we have,
n(A ∪ B) = n(A) + n(B) - n(A ∩ B)
Substituting the given values, we get,
n(A ∪ B) = 55 + 67 - x
Since the total number of students in the class is 100, we have,
n(A ∪ B) = 100
Substituting this in the above equation, we get,
100 = 55 + 67 - x
Simplifying, we get,
x = 22
Therefore, the number of students who have passed in Physics only is 67 - 22 = 45.
Hence, the correct option is (A).
In a class of 100 students, 55 students have passed in Mathematics and...
Total number of students is 100
passed in only physics is 100-67=33
(correct answer is option C)
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