a train leaves houston and travels north at 65 km/h. Aftwr it travels 150 km, it turns left and travels 60 km towards the weat at 55 km/h. what was the trains average speed answer

Question

a train leaves houston and travels north at 65 km/h. After it travels 150 km, it turns left and travels 60 km towards the weat at 55 km/h. what was the trains average speed answer

Answer 1

Let

v_n = 65 km/h be the speed travelled north,

s_n = 150 km be the distance travelled north,

t_n = s_n/v_n = 150 km / 65 km/h = 2.3 h be the time travelled north,

v_w = 55 km/h be the speed travelled west,

s_w = 60 km be the distance travelled west,

t_w = s_w/v_w = 60 km / 55 km/h = 1.09 h be the time travelled west,

s = s_n + s_w = 210 km be the total distance travelled,

t = t_n + t_w = 3.39 h be the total time travelled.

Then the average speed is

s/t = 210 km / 3.39 h = 61.9 km/h