Answer:
1/6 of the students in Robert's grade have both a sister and a brother.
Explanation:
Let x be the number of total students in Robert's grade.
It is given that In Robert's grade, 1/3 of the students have a sister.
Number of students have a sister = 
Of the students who have a sister, 1/2 also have a brother.
Number of students have both a sister and a brother = 
We need to find the fraction of the students in Robert's grade have both a sister and a brother.

Therefore, 1/6 of the students in Robert's grade have both a sister and a brother.
The Aryans invaded the Indus Valley in 326 BC.
Donaldtrumpism is the belief of restricting immigrants from entering a country.
Some media reinforce violence as a method for solving problems is: TRUE.
<h3 /><h3>Reinforcing violence as a method for solving problems</h3>
Some media platform tend to support violence in order to solve problems.
This media tend to believe that by making use of this method they can easily combat the problems or challenges.
Therefore some media reinforce violence as a method for solving problems is: TRUE.
Learn more about Reinforcing violence as a method for solving problems here: brainly.com/question/4209611
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