Question

Total time taken by a car to complete its entire journey in 3 hours it travels half journey at 90 mph and half journey at 60.Kmph how much time taken by a car to travel 90 km h

Answer 1

hey mate here is your answer

speed=distance/travel time

distance=2*40+60*3

              =80+180

              =260 km

travel time=2+3=5 hrs

∴ average speed during the whole journey=260/5

                                                                   =52 km/h

I hope it helps you mark this is answer as brainlist and follow me ❤️❤️

Answer 2

Concept:

The rate of change in an object's location over time, or the rate of change in position per unit of time, is known as its speed.

Given:

The total time taken by the car to complete the journey is 3 hours.

The car travels half the journey at 90 kilometers per hour and the other half at 60 kilometers per hour.

Find:

The time was taken to travel 90km.

Solution:

The speed of the car for half distance is 90 km/h.

Now, distance = Speed x time.

Let $2x$ be the total distance.

Then,

$x=90(t_1)\\t_1=\frac{x}{90}$

For the remaining half,

$x=60(t_2)\\t_2=\frac{x}{60}$

Now the car travels for 3 hours.

$t_1+t_2=3\\\frac{x}{90}+\frac{x}{60}=3$

$\frac{x}{30}[\frac{1}{3}+\frac{1}{2}]=3$

$\frac{5x}{30(6)}=3$

$\frac{x}{36}=3\\ x=108$

The total distance covered by the car is $2x=2(108)= 216km$.

Now,

The average speed of the car is:

$=\frac{216}{3}\\ =72 km/h$

Therefore, the time take to travel 90 kilometers is:

$t=\frac{90}{72}\\t=1.25hrs$

The time taken by the car to travel 90 km is 1.25 hours.

#SPJ2