Answer:
400 passengers
Step-by-step explanation:
To solve the problem, a proportion would be best!
First, let's set up the left side of the proportion. Percents, when used in parts, are always part of 100%, making 100% a whole. We'll use both 10% and 100% as our first fraction, which should look something like this:
(with <em>p </em>standing for <em>part </em>and <em>w</em> standing for the <em>whole</em>)
Next, let's set up the right side of our proportion. We'll use the 40 for our part and x for our whole since that is the number we are solving for. The proportion should now look like this:

To solve, just cross multiply and divide! Multiply 40 by 100 to give you 4,000. Next, divide 4,000 by the remaining 10 to give you a final answer of 400. If 40 passengers on the flight are in first class, then there are 400 total passengers. Hope this helps!
Answer:
D) Acceleration is positive and increasing.
Step-by-step explanation:
In formulae, acceleration is defined as the rate of change of velocity per unit time; for example:

where Δ V is the variation of velocity and Δ T is the variation in time.
The graph depicts the velocity of a moving item as a function of time. As we can see ΔV is the increment on the y-axis, while ΔT is the increment on the x axis: therefore, the ratio ΔV/ΔT is the curve's slope. In fact, the slope of the curve in a velocity-time graph corresponds to the object's acceleration. In this graph, we can see that the slope of the curve is growing, which means that the acceleration is positive (since the slope is positive and the velocity is increasing) and increasing (because the slope is increasing).