Answer:
25°
Step-by-step explanation:
The maximum extent of the sprayed area is 40° +75° = 115°. So, the wiper going to 140° goes 140°-115° = 25° beyond the sprayed area.
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The graph attached is a crude representation of the problem. The overlapping blue and red areas are the area covered by the windshield wiper, starting at 0° and going to 140°. The green sector is that covered by the spray, starting at 40° and going to 115°.
