The average speed of the car for the entire trip can be calculate by using:

where S is the total distance covered by the car, and t is the total time taken.
The total distance travelled by the car is:

while the total time taken is:

so, the average speed of the car is:

so, the correct answer is (3) 85 km/h.
Ok so I already studied this and I realized it was water or also Oxygen
The friction is 2.5N. The Net force is 10 N - 2.5 N .= 7.5 N.
acceleration = 7.5 / 5 = 1.5 m/s^2
Using V= vo +at with Vo = 0 and a= 4m/sec2.
V= 0+ 4x8= 32m/s
Answer: The Electrostatic force of attraction or repulsion between two charges shows that the Newton's third law applies to electrostatic forces.
Explanation: Consider two Oppositely charged charges separated by distance d.
The electrostatic force exerted by charge 1 on charge 2 is.
By Coulomb's Law :
F1 = k
.....................................(1)
The electrostatic force exerted by charge 2 on charge 1 is.
F2 = - k
................................. (2)
negative sign shows that force are in opposite direction.
From Equation 1 and 2
F1 = - F2
Which implies Newton Third law.