Hey!
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Solution:
1/2 are younger than 10.
1/20 are 10 years old.
1/10 are older than 10 but younger than 12.
70 are 12 years old.
Find Common Denominators.
1/2 = 10/20
1/20 = 1/20
1/10 = 2/10
Add.
10/20 + 1/20 + 2/10 = 13/20
Subtract.
20/20 - 13/20 = 7/20
So we now see that 7/20 = 70
Now we can see that 1/20 = 10
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Answer:
There are 10 students that are 10 years old.
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Hope This Helped! Good Luck!