Question

Question 12 (2 points)
Find the three arithmetic means between -5 and -25.

Answer 1

The arithmetic means are - 10, - 15, and - 20.

Explanation:

Let the arithmetic means are p, q, and r.

So, - 5, p, q, r, and -25 are in A.P

Therefore, the first term is - 5 and the 5th term is - 25.

If the common difference is d of the A.P., then

- 25 = - 5 + (5 - 1)d

⇒ 4d = - 20

⇒ d = - 5.

Therefore, p = - 5 - 5 = - 10.

q = - 10 - 5 = - 15 and

r = - 15 - 5 = - 20

Therefore, the arithmetic means are - 10, - 15, and - 20. (Answer)