I believe the answer is 27/30
C. The way the sample was chosen may overrepresent or underrepresent students taking certain language classes.
The samples he chose may not be a representative sample because the number of students per foreign language class may not be the same. Since classes have different numbers of students, one may have a very large number of students while another may have only a few. Taking equal number of students per class is not a representative sample because it doesn't represent the students correctly.
Answer:
90 kg of stone
Step-by-step explanation:
Adam has 8 x 25 = 200
19 x 22.5 = 427.5
20 x 50 = 1000
He has enough cement and sand
He needs 1090 - 1000 = 90 kg of stone
He needs 2 bags of stone
