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.
Answer:
A
Step-by-step explanation:
I'd say the 3rd one. I haven't done this stuff in 2 years ... me forgot. But if it's not right, then the 1st one!
I want you to know you're smart and you can do this! Good luck!
Are you asking if this is greater than, less than, or equal to?
The answer would be 10! I divided the number of plants that you can water with 4 gallons (14) by, well, the number of gallons it takes to water them (4) and got 3.5 (14 / 4 = 3.5), the number of plants you can water with one gallon. I then divided the number of plants you need to water (35) by the number of gallons it takes to water one plant (3.5) and came up with 10. I hope this helps you!