In a group of 33 teachers in a high school, 7 teachers teach chemistry, 19 teachers teach physics and 18 teachers teach mathematics. Also, 3 teachers teach both chemistry and physics, 8 teachers teach both physics and mathematics and none of teachers teach both chemistry and mathematics. Then, find the number of teachers who teach only chemistry?
In a group of 33 teachers in a high school, 7 teachers teach chemistry, 19 teachers teach physics and 18 teachers teach mathematics. Also, 3 teachers teach both chemistry and physics, 8 teachers teach both physics and mathematics and none of teachers teach both chemistry and mathematics. Then, find the number of teachers who teach only chemistry? Correct Answer 4
Given:
Total number of teachers = 33
Teachers who teach chemistry = 7
Teachers who teach physics = 19
Teachers who teach mathematics = 18
Teachers who teach both chemistry and physics = 3
Teachers who teach both physics and mathematics = 8
Teachers who teach both chemistry and mathematics = 0
Concept:
Venn Diagram
Calculation:
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The number of teachers who teach chemistry and mathematics = 0
∴ The number of teachers who teach all three subjects = 0
The number of teachers who teach only chemistry and mathematics = 0
The number of teachers who teach only chemistry and physics = 3 – 0 = 3
∴ The number of teachers who teach only chemistry = 7 – 3 = 4
