If three arithmetic means are inserted between 5 and 25, the second arithmetic mean is _____?
If three arithmetic means are inserted between 5 and 25, the second arithmetic mean is _____?
Explanation
5, _, _, _, 25
There are 5 terms. Let's find the common difference:
d = 25-5/4 = 20/4 = 5
The sequence is:
5 + 5 = 10
10 + 5 = 15
15 + 5 = 20
20 + 5 = 25
The sequence is 5, 10, 15, 20, 25
The second arithmetic mean is 15.