Question

15.
A car travels the first half of a certain distance with a speed of 30
km/h and the second half with a speed of 50 km/h. Find the average
speed of the car?​

Answer 1

Answer:

sum of speed /number of speed

50+30/2

80/2=40

=40 km/h

Explanation:

therefore average =40km/h

Answer 2

Answer:

24 km/h

Explanation:

given that:

speed in first half = 30 km/h

speed in second half = 50 km/h

let,

d=distance traveled in first half and second half

t1= time taken in first half

t2= time taken in second half

time = distance/speed

they are: t1 = d/30 km/h

              t2 = d/50 km/h

average speed = total distance/total time

$average speed = total distance/total time\\\\                          = d+d/d/30+d/50\\                          = 2d /2d+3d/60\\                          = 2d/5d/60\\                         = 2d * 60/5d\\= 2*d * 60/5*d\\= 2*12= 24 km/h\\\\therefore the average speed = 24 km/h$