Answer:
1120 combinations of four teachers include exactly one of either Mrs. Vera or Mr. Jan.
Step-by-step explanation:
The order in which the teachers are chosen is not important, which means that the combinations formula is used to solve this question.
Combinations formula:
is the number of different combinations of x objects from a set of n elements, given by the following formula.
In this question:
1 from a set of 2(Either Mrs. Vera or Mr. Jan).
3 from a set of 18 - 2 = 16. So

1120 combinations of four teachers include exactly one of either Mrs. Vera or Mr. Jan.
<h2>
B)</h2>
It is <em><u>400</u></em>. Since 5 x 8 = 40 add the 0 to the end its 400!!
Hope this helps <33!!
Answer:
B
Step-by-step explanation:
its b solve the first equation for y \
hope this helps
brainliest would be appreciated
I believe it is the first one
The area of the door is 16ft (4x4) and the window is 900 (30x30) then do 900/16= 56.25 I hope I'm right!