So there are different ways this could be solved. I'll do try to explain it the way I was taught...
Simon is riding his bike at 12 km/hr relative to the sidewalk, away from where Keesha is.
Simon throws the ball at Keesha, at 5 km/hr.
Keesha sees the ball approaching her at (12-5) = 7 km/hr relative to the ground to her.
Therefore the answer is: 7 km/hr
Explanation:
Below is an attachment containing the solution.
This question involves the concepts of work done, pressure, and temperature.
The work done per mol of the air is "-724.71 J/mol".
Using the given formula for work done:

where,
W = work done per mol = ?
R = universal gas constant = 8.314 J/mol.k
T = absolute temperature = 30°C + 273 = 303 k
P₁ = initial pressure = 30 KPa
P₂ = final pressure = 40 KPa
Therefore,

<u>W = -724.71 J/mol</u>
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Learn more about pressure here:
brainly.com/question/23358029?referrer=searchResults