Answer:
110 cm^2
Step-by-step explanation:
The first thing that you need to do is find the area of triangle AFE. The area of a triangle is always base*height/2. So in this case, that would be 10*6 divided by 2, which is 30 cm. Next, you will need to know the area of triangle ECB. Using that same formula, you will get 8*10/2, which is 40 cm. Finally, you will need to find the area of the whole rectangle. The area of a rectangle is always the length times the width. In this case, you would have 10*18, which is 180 cm. To get your final answer, you need to subtract the areas of the unshaded area from the whole area. That would be 180-(30+40), which is 110 cm. I hope this helped!
Assuming that each marble can be picked with equal probability, we notice that there is a total of
marbles, of which 2 are red.
So, the probability of picking a red marble is
In fact, as in any other case of (finite) equidistribution, we used the formula
