Find

by plugging in 1 into n:

Find

by plugging in 11 into n:


Now to find the sum your formula is:


Now plug that into the formula


Hope that helps
You are right the answer is A
Answer:
The dog could have had rabies
Step-by-step explanation:
Answer:
6
Step-by-step explanation:
Let
. We know the formula for the sum of an arithmetic sequence is:

Where n is the number term you are finding the sum up to, a1 is the first term, and an is the nth term. We can substitute what we have:


The formula to find the nth term of an arithmetic series is:

Where d is the common difference. Again, we can plug in what we have;

5x2 correct is the answer