Draw a sketch! So you have an opportunity to control your arithmetic results.A radar buoy detects any boats within a radius of 12 miles. A rowboat starts at a location 18 miles south and 10 miles east of the radar buoy. The rowboat travels at a constant speed of 15 mph. The tugboat travels on a straight line toward the northermost point of the radar region. When the tugboat is directly east of the buoy, it turns and travels due north until it exits the radar region.
How long (in hours) is the tugboat in the radar region?
This is what I did:
So first path: y = -3x + 12 <--- OK
Where it crosses
9) x = 0 or x = 7.2 <--- OK
So now I know x=0 is my point
Our point (0,12)
If x = 7.2
10) y = 3(7.2) + 12 = 33.6 <--- this is wrong: The slope has the value -3
So the intersection of his path with the radar region is (7.2, 33.6)
I crosses the x-axis at x = -4 , (let y=0 in y = 3x+12 )