Start by proving to them that the number 0.57 can be converted into a fraction . A whole number can't exactly be put in to a fraction. 0.57 can be converted to 14.25/25. This information means that 0.57 IS a rational number. Hope this convinced them!
Answer: 72 cars.
Step-by-step explanation:
Let be "x" the number of toys that Moby had to start with.
According to the information given in the exercise, Moby sold half his toy car collection. This can be represented with the following expression:

Then he bought 12 more cars, giving a total amount of 48 toy cars.
Therefore, the equation that represents this situation is the equation shown below:

Now you must solve for "x" in order to find its value.
You get that this is:

An easy way of finding the answer to your question is by using a scientific calculator. When I plugged in 6,000^10 it gave me 6.0466176x10^37. Yes the answer is in scientific notation, but if you want the answer shortened out to the nearest hundredth place the answer is 6.05.
Since the problem is not telling us the height of Silvio, we are going to assume it is not relevant for our calculations.
Let

the altitude of the incoming plane. We know for our problem that the distance between Silvio and the tower is 3 miles, Also we know that the angle of elevation to the plane is 40°. With this information we can create a triangle as shown in the figure. We need a function that relates the angle of elevation with its opposite and adjacent sides, that function is tangent.




We can conclude that we should use the trig function tangent to model this situation; also, we can conclude that the equation that describes this situation is

.