Question

in an AP if a=1, a11= 20 and Sn= 399, then 'n' is???? a.19 b.21 c.38 d.42.......... please answer fast..........plsss​

Answer 1

Answer:

The Correct answer is c)

Step-by-step explanation:

Hope this will help you sister

Answer 2

Answer:

good afternoon sister♥️