Three trains A B C leave Diridion station at the same time T

Three trains A, B, C leave Diridion station at the same time. The relationship between time and distance for each train is a linear function described below:

Train A: Distance (miles): 0, 40, 80, 120, 160, 200

               Time (Hours):   0, 1, 2, 3, 4, 5, 6, 7

Train B S(t) = 45t

Train C:

Time(hours)

Distnace (miles)

3

105

6

210

9

315

12

420

a) What is the rate of change of S(t)?

b) How fast is Train A moving?

c) Which train is moving faster, Train A, B or C?

Solution

a.Rate of change of s(t) =(s(2) -s(1))/(2-1) = 45miles per hour

b. speed of train A is=40/1miles per hour= 40 miles per hour

c. speed of train A is 40 ,of B is 45 and of C is 35miles per hour.

Therefore B is faster.