Statistic significance requires that your sample be representative of the population, but I'm struggling with this because if the class is an elective then the answer would be: <span>No, it is not a valid inference because she asked all 22 students in her science class instead of taking a sample of the students in her school.
BUT if the class is required, as most science classes are, then it WOULD be a random sample of the school. So the last option would be correct.
My guess though is that the teacher is looking for answer B.
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Say x is the number of weeks until their money is equal. Then, we can set up an equation.
400 + 25x = 250 + 75x
Subtract 250 from both sides
150 + 25x = 75x
Subtract 25x from both sides
150 = 50x
Divide by 50 on both sides
3 = x
That means the answer is 3 weeks.
Answer:
12
Step-by-step explanation:
All sides are the same
