Answer:
First question:
We can start by setting up the formula that relates the volume V, temperature T, and pressure P:
V = k * (T/P)
where k is a constant of proportionality. We can solve for k by plugging in the given values for V, T, and P:
70 = k * (420/18)
Simplifying the right side of the equation, we get:
70 = k * 23.3333
Dividing both sides by 23.3333, we get:
k = 3
Now we can use this value of k to find the temperature T when V is 60 cm and P is 7:
60 = 3 * (T/7)
Simplifying the equation, we get:
T/7 = 20
Multiplying both sides by 7, we get:
T = 140
Therefore, the temperature when V is 60 cm and P is 7 is 140 kelvin.
Second question: We can start by using the formula that relates the time (T), distance (D), and speed (S):
D = S * T
Since the distance between the two cities is constant, we can set the distances for the two cars to be equal:
35 * 9 = 21 * T
Simplifying the right side of the equation, we get:
315 = 21T
Dividing both sides by 21, we get:
T = 15
Therefore, the trip takes 15 hours for a car moving at 21 mph.
Hopefully this helps you! I'm sorry if it wrong. If you need more help, ask me! :]