Speed boat departed 1.75 hrs after steam boat 1.8 hrs after speed boat departure, steam boat has sailed for a total: 1.8+1.75 = 3.55 hrs steam boat's speed is 36.8 km/hr, so it has traveled: 3.55*36.8 = 130.64 km
speed boat is 86.9 km behind steam boat. so it is 130.64-86.9 = 43.74 km from port speed boat's speed = 43.74/1.8 = 24.3 km/hr
In order to solve this you need to graph the points and then draw a line threw them. The place where the line crosses through the y-intercept is the value for b in y=mx+b.
