SOLUTION: A Grade 8 class is planning to have a field trip. The survey showed that if the contribution is $200., 12 students will join and if the contribution will be reduced to $160, 20 stu

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Question 979993: A Grade 8 class is planning to have a field trip. The survey showed that if the contribution is $200., 12 students will join and if the contribution will be reduced to $160, 20 students will join. How can you predict the number of participants for any given contribution (x)?
Answer by josgarithmetic(39630) About Me  (Show Source):
You can put this solution on YOUR website!
The description gives two data points.
Using x for the contribution quantity and y for the number of students that join, the points are (200,12) and (160,20). Your decision of what kind of relationship fit do you use. You might want a linear fit.

slope, m=%2820-12%29%2F%28160-200%29=8%2F%28-40%29=-1%2F5.

vertical intercept, b=y-mx, choose either point,
b=12%2B%281%2F5%29200=12%2B40=32.

highlight%28y=-x%2F5%2B32%29