Niles and Bob sailed at the same time for the same length of time. Niles' sailboat traveled 30 miles at a speed of 6 mph, while Bob's motorboat traveled 70 miles at a speed of 14 mph. For how long were Niles and Bob traveling?

5 hours

Step-by-step explanation:

As both of them sailed for the same time, take the speed and distance of either of them to find the time they traveled:

Niles' Time = Distance / speed

= 30 / 6

= 5 hours

Bob's time = 70 / 14

= 5 hours  

check above link.

graphically?   well, you graph them both, the solutions is where they both intersect each other, since there are two solutions, meaning they will meet twice, or namely the linear will run into the quadratic curve twice, and where they meet, those x,y coordinates are the solutions to the system.