Question

​If 11 arithmetic means are placed between 7
and 31, then the common difference will be :​

Answer 1

Let the common difference be d.

Now since you have placed 11 terms between 7 and 31.
So the total number of terms will be 9.

So the first term here will be 7.
I'm gonna denote it using a.

a =7
and the last term will be a +(9-1)d which is equal to 31.


$a + (8)d = 31 \\ 7 + 8d = 31 \\ 8d = 24 \\ d = 3$



Therefore the common difference will be of 3.