Answer:
v=31
Explanation:
Average speed is total distance/total time.
We can rearrange this equation to find total distance:
Distance = time x speed
Our given time is 14 hours and our average speed is 13km/h, therefore the distance travelled 14x13=182m.
On a speed-time graph, the distance is found by finding area under the line on the graph. So to find v, we can find the area for the other sections first and then use the remainder to find v.
The total distances for the other 3 sections are: 4x6 + 6x12 + 4x12 = 24+72+24=120
182-144 = 38
This means that the area of the triangle with height v-12 has an area of 38.
Area of a triangle = 1/2bh
38=1/2(4)h
38=2h
h=19
The distance between v and 12 is 19 so the full value of v is 19+12=31
v = 31
Hope this helped!