Answer:
Tree diagrams display all the possible outcomes of an event. Each branch in a tree diagram represents a possible outcome. Tree diagrams can be used to find the number of possible outcomes and calculate the probability of possible outcomes.
Step-by-step explanation:
Using the combination formula, it is found that the integers can be chosen in 870 ways.
<h3>What is the combination formula?</h3>
is the number of different combinations of x objects from a set of n elements, given by:

The resulting sum will be even if both numbers are even(2 from a set of 30) or if both numbers are odd(also 2 from a set of 30), hence:

The integers can be chosen in 870 ways.
You can learn more about the combination formula at brainly.com/question/25821700
Answer:
I will answer in a general way because the options are not given.
We know that the area of model A is smaller than the area of model B.
For model A, we have 72 shaded sections, out of 100.
Then the quotient of model A is:
72/100 = 0.72
For model B we have 10 sections, and x shaded ones.
Because model B is greater than model A, we know that:
x/10 should be larger than 72/100
then we have the inequality:
x/10 > 0.72
x > 0.72*10
x > 7.2
And we can not have more than 10 shaded sections (because there is a total of 10 sections) then:
10 ≥ x > 7.2
Then x can be any whole number in that interval.
the possible values of x are:
x = 8
x = 9
x = 10
2(x+2) = 60
x+2 = 30
x = 28
The correct answer is C