Question

a car travels the first half of a distance between two places at a speed of 30 km per hour and the second half of the distance at 50 km per hour the average speed of the car for the whole journey is..... note that the true answer is 37.5 kilometre per hour...pleaseh help​

Answer 1

let the total distance be 2x

therefore the car travel s first half distance I.e. x with 30 km/hr

time = x/30 hr

the car travel s second half of the distance I.e x with 50km/hr

time = x/50 hr

now,

average speed= total distance travelled/total time taken

= 2x/x/30+ x/50

= 2x/5x+3x/150

= 2x/8x*150

= 150/4

= 37.5km/hr

Answer 2

Explanation:

let the total distance of journey be x km

for half journey, x/2

let T, be time taken

T, =x/2×30

T,= X/60

for another half journey x/2

let T be time taken

T= ×/2×50

T= x/100

Now ,for average speed

total time = T,+T= ×/100+×/60

total distance =×

Average speed = x

_________

x/100+ ×/60

=300X

____________

3x+5×

=300/8

= 37.5 kilometer per hour

.I thik it help you