BO is double that of DO. In other words, BO is two times longer than DO. The answer is choice B
For example, if DO were 3 units long, then BO would be 6 units long (2*3 = 6). This works because the triangles DCO and BAO are similar triangles. The corresponding sides are in the same ratio or proportion to one another. The larger triangle (BAO) has sides that are twice as long as the smaller triangle's (DCO) corresponding sides.
Side note: we can prove the triangles to be similar using the AA (angle angle) similarity theorem. The first pair of angles are the vertical angles DOC and BOA which are congruent to each other.The second pair is CDB and ABD which are congruent by the alternate interior angle theorem. Check out the attached image for a visual.
Part A) x-intercepts simply show that when the value of the function is zero. Vertex coordinates show that when the function obtains its maximum value. When x=50, function obtains its maximum value and it's 75. The function is increasing in the interval (0, 50) and decreasing in the interval (50, 100). In regard to the height and distance of the tunnel, these numbers show that decreasing and increasing intervals are symmetric. Each number from the intervals has its own pair in the corresponding interval and they are located in the same distance from the midpoint (50,75)
Part B) In order to calculate the average rate of change, we can first write the function. Using the information about the x-intercept and the vertex coordinates, we find that our function is

.
Plugging 15 and 35 in x, we can find the values of the function, i.e.

and

.
Then, the average change is
Answer:
He told me that he was a nice fellow
I told him that he looked sad and tired
She told me that I was a clever person
She told them that they could pass their exams if they worked hard
Sabnam said that she had gone to the hospital the previous day
Shilpa said that she had been extremely nervous the previous week
Husaain said that they had gone to bed early the previous night
Rahul said that he had not taken a taxi home the previous night