Question

Q5. A train travels along a straight line at a constant speed of 60 km/h for a distance d and
then another distance equal to 2d in the same direction at a constant speed of 80 km/h.
a) What is the average speed of the train for the whole journey?
tmunir 27 km south 12 km west, and 14 km north in half an hour.​

Answer 1

Answer:

Step-by-step explanation:

Case 1:

s = 60km/h

d = d km

t = d/s = (d/60)h

Case 2:

s2 = 80 km/h

d2 = 2d km

t2 = d2/s2 = (d/40)h

avg. s = (3d/5d) x 120

= 3 x 24

= 72 km/h or 20 m/s

Hope this helps . I don't understand the last part . Sorry for inconvenience.

Answer 2

Answer:

Step-by-step explanation:

The time t1 to cover distance d at a speed of 60 km/h is,t1=d60The time t2 to cover distance 2d at a speed of 80 km/h is,t2=2d80Average speed=total distance total time Average speed=d+2dd60+2d80Average speed=3d4d+6d240Average speed=3d×24010d=72 km/h The time t1 to cover distance d at a speed of 60 km/h is,t1=d60The time t2 to cover distance 2d at a speed of 80 km/h is,t2=2d80Average speed=total distance total time Average speed=d+2dd60+2d80Average speed=3d4d+6d240Average speed=3d×24010d=72 km/h

Hope it helps!