Answer: The correct answer is option(A).
Explanation:
Total forces exerting on the car = F
= Force on car exerting in right direction
= Force on car exerting in left direction
= Force on car exerting in upward direction
= Force on car exerting in downward direction

(negative sign shows the direction)
Since, upward force are equal in magnitude but opposite in direction by which they will balance out each other.so, the net force car will be due to two forces
and 
(negative shows the direction)
The magnitude (size) and direction of the cumulative force acting on the car will 30 N towards right direction.Hence, correct answer is option(A).
This is an incomplete question, here is a complete question.
The Henry's law constant for oxygen dissolved in water is 4.34 × 10⁹ g/L.Pa at 25⁰C.If the partial pressure of oxygen in air is 0.2 atm, under atmospheric conditions, calculate the molar concentration of oxygen in air-saturated and oxygen saturated water.
Answer : The molar concentration of oxygen is, 
Explanation :
As we know that,

where,
= molar solubility of
= ?
= partial pressure of
= 0.2 atm = 1.97×10⁻⁶ Pa
= Henry's law constant = 4.34 × 10⁹ g/L.Pa
Now put all the given values in the above formula, we get:


Now we have to molar concentration of oxygen.
Molar concentration of oxygen = 
Therefore, the molar concentration of oxygen is, 
Answer : The number of moles in 369 grams of calcium hydroxide is, 4.98 moles
Explanation : Given,
Mass of calcium hydroxide = 369 g
Molar mass of calcium hydroxide = 74.093 g/mole
Formula used :

Now put all the given values in this formula, we get the moles of calcium hydroxide.

Therefore, the number of moles in 369 grams of calcium hydroxide is, 4.98 moles