Question

A plane travels 200km at 150 km/h, 300km at 200 km/h and 400km at 250km/h all at a constant speed.

Answer 1

$\leq$Answer:

Step-by-step explanation:

The distance, D, is given by the speed, S, times the time, T:  

D = S*T

D        S*T               Time          Equation for each segment

200 =  150T1  T1 = 1.33 hr       y=150x         0  $\leq$ T $\leq$ 1.33  hr

300 = 200T2  T2 = 1.5 hr       y=200x     1.33 $\leq$ T $\leq$ 2.83  hr

400 = 250T3  T3 = 1.6 hr       y=400x     2.83 $\leq$ T $\leq$ 4.43  hr

The graph can be drawn as three lines, ione each for the three segments, each having the slope shown in the equation for that segment and extending between the range of values for T (which is the "x" in the equation and on the graph).  The y axis will be ditance, in km.

The overall speed is the total distance divided by the total time:

    D(km)      T(hr)

1)     200       1.33

2)    300       2.83-1.33 = 1.5

3)    400       4.43-2.83 = 1.6

      900 km          4.43 hr

(900 km)/(4.43 hr)

Average speed = 203.01 km/hr