Answer:
Step-by-step explanation:
Let the speed of the car is c and speed of the plane is p.
<h3>We are given:</h3>
The speed of the plane is 7 times the speed of the car
The distance traveled is
The time difference to travel this same distance is 3 hours.
<h3>We know that:</h3>
- d = ts, where d- distance, t- time, s - speed
Find the time for car and plane and their difference.
<h3>Car</h3>
<h3 /><h3>Plane</h3>
- t = d/s = 315/p = 315/(7c) = 35/c
<h3 /><h3>The difference</h3>
<u>Solve it for c:</u>
- (315 - 45)/c = 3
- 270/c = 3
- c = 270/3
- c = 90 km/h
Now find the speed of plane:
As we see, Jenny is right
