In a certain class, 4/7 of the students are boys, and the ratio of the students older than or equal to 10 years to the students less than 10 years old is 2:3. If 2/3 of the girls are less than 10 years old, what fraction of the boys are older than or equal to 10 years?
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Sam_PrepScholar |

Now, we can use the variable x as a stand-in for the number of boys that are 10 years old or older. The number of boys who are younger than 10 can be represented by the expression 40-x (subtract x from the total number of boys in the class). To find x, we would use the 2:3 ratio. Simplified, the expression looks like (x+10)/(60-x) = 2/3. Then, x+10 = 40 - (2/3)x, and (5/3)x = 30. With this expression, x comes out to be 18. Now remember, we're looking for the fraction of the boys that are older than or equal to 10 years, so 18 isn't the final answer.
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