Part A is 6 and the bottom one is "Take a line and connect it from point C to the middle of A and B then put another line connecting to D to the middle of A and B"
Slope of a line passing through these two points is
.
Hope this helps.
We know, Time = distance / speed
t = 0.0568182 / 50 [ 300 Feet = 0.0568182 miles ]
t = 0.001136 * 3600 s
t = 4.09 sec
In short, Your Answer would be 4.09 Seconds
Hope this helps!