Question

A train travels at 60km/hr for 0.52 h , at 30km/hr for the next 0.71 hr. what is the average speed of the train .​

Answer 1

Answer:

i) In the first case, the train travels at a speed of 60 km/h for a time of 0.52 h

Now, Speed = distance / time = 30km/hr

Distance = 60 x 0.52 = 31.2 km --- i)

(ii) In the second case, the train travels at a speed of 30 km/h for a time of 0.24 hr.

Now, speed = distance / time = 30 km/hr

Distance = 30 × 0.24 = 7.2 km --- ii)

(iii) In the third case, the train travels at a speed of 70km/h for a time of 0.71 hr.

Now, speed = distance / time = 70km/hr

Distance = 70 × 0.71 hr .

Now speed = distance / time = 70km/hr

Distance = 70 × 0.71 = 49.7 km ---iii)

From equation 1,2 & 3 we get,

Total distance travelled

= (31.2 + 7.2 + 49.7) km = 88.1 km .

Total time taken = (0.52 + 0.24 + 0.71) hr = 1.47 hr .

Average speed = Total distance travelled / Total time taken

= (88.1/1.47) km /hr

Hence, average speed = 59.9 km/hr