Answer:
350
Explanation:
We have two points on the demand curve as (10, 450) and (15, 200). Using the two-point form of the equation for the line between them, we can find the "y" value for "x" = 12 as ...
y = (y2 -y1)/(x2 -x1)(x -x1) +y1
y = (200 -450)/(15 -10)(12 -10) +450
= (-250/5)(2) +450
= -100 +450 = 350
We predict the number of tickets sold at $12 will be 350.
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Check
The drop in sales of 50 tickets for each $1 increase in price is consistent with other table values.