Sarah paid a food bill of $13.74 with a $20 bill. how much change was she owed?

What is the slope of a line that is perpendicular to y = 3x + 1

On traditional maps, earth is represented in a flat plane, or by euclidean geometry. however, a globe is a more accurate model that comes from elliptical geometry. how does a globe represent the fact that there are no parallel lines in elliptical geometry? the equator is not parallel to any other latitudinal lines. the north and south poles are never connected by a geodesic. the geodesics connecting the north and south poles never intersect. the geodesics connecting the north and south poles intersect at both of the poles.

Tom drove 206 miles in 3.9 hours. estimate his average speed.