## Answer & Solution

Answer:** Option C**

Solution:
1^{st} Method:

8th term = a+7d = 39 ........... (i)

12th term = a+11d = 59 ........... (ii)

(i)-(ii);

Or, a+7d-a-11d = 39-59;
Or, 4d = 20;

Or, d = 5;

Hence, a+7*5 = 39;

Thus, a = 39-35 = 4.

2nd Method (Thought Process):

8th term = 39;

And, 12th term = 59;

Here, we see that 20 is added to 8th term 39 to get 12th term 59 i.e. 4 times the common difference is added to 39.

So, CD = 20/4 = 5.

Hence, 7 times CD is added to 1st term to get 39. That means 4 is the 1st term of the AP.