What is the sum of all the odd integers between 8 and 56?

Find the 51st term of the sequence $$a_n=\frac{\left(-1\right)^n\left(2n-1\right)}{2}$$   .

If there are six arithmetic means between $$-\frac{1}{5}$$   and -3, what is the 2nd mean?

What is the sum of all the multiples of 3 from 15 to 48?

What is the arithmetic mean between $$\frac{1}{2}$$   and 2?

Find the arithmetic means between 87 and -12 such that the sum of the resulting sequence is 150.

Find p so that the numbers 7p+2, 5p+12, 2p-1, … form an arithmetic sequence.

Find the sum of the first 15 terms of the arithmetic sequence whose general term is $$a_n=5n+3$$  .