Me solve this ,it's systems of equations word promblem. explain also, you : )1) a boat traveled 210 miles downstream and back. the trip down stream toom 10 hours. the trip back took 70 hours. what is the speed of the boat in still water? what is the speed of the current?

Let c be the speed of the current and b the speed of the boat in still water (I assume is constant rate)D=RT, distance = rate x timethe distance is 210 in each directionthe rate downstream (current pushing the boat forward) is b+cthe rate upstream (current dragging against the boat) is b-c210 = (b+c) x 10 (downstream)210 = (b-c) x 70 (upstream)
dividing both sides of top equation by 10 and bottom equation by 70 we have21 = b+c3 = b-cadding the left & right sides of the top equation to L&R sides of bottom equation, we have24 = 2b (eliminating c)b = 12 andc=9, since 3 = 12-cSo, the speed of the boat in still water is 12 mph and the speed of the current is 9 mph

A. Line Graph 

Line graphs are the best for comparing information and how it changes over time :)