Answer:

Step-by-step explanation:
The nth term of an arithmetic sequence is given by the formula,

We were given that the 9th term is
.





The sum of the first n-terms is given by the formula,

To find
, we substitute
,
and
.





The correct answer is D
Answer:
11 months
Step-by-step explanation:
the math that i did was i kept adding 400 to 2500 and counted every four hundred that i added witch was 11 until i got to 7000 so the answer is 11 months. You will have some left over which you will have 300 left over.
67-x-20 hope this helped!!
Answer:
36
Step-by-step explanation:
90÷5=18
18×2=36
We multiply two because the ration for adults is 2