Answer:the speed of postman from A to B is 6 km/hr
Step-by-step explanation:
Let x represent the speed of the postman when moving from A to B.
From point A, the postman delivered a letter to point B in half hour.
Distance = speed × time
It means that
Distance from A to B = 0.5 × x = 0.5x
In back way he reduced speed by 1km/h and gets back in 36 min. It means that his speed on returning back would be (x - 1)km/h
Converting 36 minutes to hour, it becomes
36/60 = 0.6 hours
Distance from B to A = 0.6(x - 1)
Since distance from A to B = distance from B to A, then
0.5x = 0.6(x - 1) = 0.6x - 0.6
0.6x - 0.5x = 0.6
0.1x = 0.6
x = 0.6/0.1 = 6
