Question

A motocylist drives from place A to B with a uniform speed of 30 in h`-1 and retur from place B to A with uniform speed of 20 km h-1 find its average speed​

Answer 1

hey mate

here is the answer..

Answer:

the average speed:

2xy/x+y

=>2*30*20/(30+20)

=>1200/50

=>24 km/hr

explanation:

let the distance between a and b between be D km .

let the speed be x km/hr to travel from a to b.

let the speed be y km/hr to travel from b to a.

thus,

time to travel from a to b=D/x hr

time to travel from b to a =D/y

thus,

the average speed=total distance/total time

=(D+D)/(D/x+D/y)

=2D/D(x+y)/xy

=2xy/x+y

Answer 2

short cut for this example is
if travelld distance in first and last moment 8s same then,
avg. speed= 2xy/x+y
where as x and y are two speed with which we travel

there fore ans.= 24kmph