Answer: 675
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Step-by-step explanation:
Start at $3.50 on the vertical y axis. Draw a horizontal line until you reach the supply curve. Then drop straight down to land somewhere between 650 and 700 units supplied per day. Check out the diagram below.
A good estimate may be to use the midpoint. Add up those values and divide in half.
(650+700)/2 = 1350/2 = 675
Therefore, we estimate that 675 sandwiches per day would be supplied if the price was $3.50 per sandwich.