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Answer :

Mhanifago

Answer:

  • Yes

Step-by-step explanation:

Let the speed of the car is c and speed of the plane is p.

We are given:

The speed of the plane is 7 times the speed of the car

  • p = 7c

The distance traveled is

  • d = 315 km

The time difference to travel this same distance is 3 hours.

We know that:

  • d = ts, where d- distance, t- time, s - speed

Find the time for car and plane and their difference.

Car

  • t = d/s = 315/c

Plane

  • t = d/s = 315/p = 315/(7c) = 35/c

The difference

  • 315/c - 45/c = 3

Solve it for c:

  • (315 - 45)/c = 3
  • 270/c = 3
  • c = 270/3
  • c = 90 km/h

Now find the speed of plane:

  • p = 7c = 7*90 = 630 km/h

As we see, Jenny is right

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