Question

Please solve the question and give correct answer with explanation so that i can understand it​

Answer 1

• Yes

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