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 )

...