Slope of line is 31 and tells that in every minute 31 hats are being manufactured.
Explanation:
The slope of a line characterises the direction of a line. To find the slope, you divide the difference of the y-coordinates of 2 points on a line by the difference of the x-coordinates of those same 2 points.
Also, slope of line can be found by trigonometry, as slope is Tan∅ where ∅ is angle between lines y and x. In above case we have, 310 hats which are being manufactured in every 10 minutes that means on Y-axis we have Number of hats and on X-axis we have count off minutes .
So slope = Tan∅ =

Perpendicular = 310 & base = 10
∴

Hence every minute 31 hats are being manufactured.