Answer: 9/20
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Step-by-step explanation:
We add up the fractions given
1/5 + 1/4
4/20 + 5/20
(4+5)/20
9/20
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An example:
Let's say there are 20 students.
- 1/5 of 20 = (1/5)*20 = 4 students have glasses
- 1/4 of 20 = (1/4)*20 = 5 students wear contacts
Assume that those who wear glasses do not wear contacts, and vice versa. In other words, assume someone doesn't use both types.
If that assumption holds up, then 4+5 = 9 students wear corrected vision of some sort. So that's how we can arrive at the answer of 9/20 as the fraction of corrected vision students.