hi
40 students
30 read chemistry
20 read physics
so logical deduction is that 10 read chemistry and physics.
So only 20 read only chemistry and only 10 read only physics.
So read only chemistry is 20/40 = 1/2
Answer as a fraction = 1/2
Answer in decimal form = 0.5
Answer in percent form = 50%
All three represent the same idea, but in a different form.
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Work Shown:
30 read chem, 20 read physics
30+20 = 50 read either one, but this is over 40, so 50-40 = 10 students must read both
From that,
30-10 = 20 read chem only
20-10 = 10 read physics only
This makes the venn diagram you see below
Divide the number of people who read chemistry only (20) over the total number of people (40). This gives 20/40 = 2/4 = 1/2
Then you would use your calculator to find 1/2 = 0.5 = 50%
