the friendship trail is a multi-use recreational trail that runs from port colbornen to fort erie, a distance of 25 km. at 2pm, debbie starts rollerblading from port colborne at 10 km/h. at the same time, ken starts bicycling from fort erie at 20 km/h. when will they meet eachother? how far from fort erie will they be at this time?

hello! just here for points! though i wish i knew!

sample answer: you can determine whether each element of the domain is paired with exactly one element of the range. for example, if given a graph, you could use the vertical line test; if a vertical line intersects the graph more than once, then the relation that the graph represents is not a function.