An athlete prepares for the Comrades. He jogs out to a certain point and then turns back home. On the first day he turns after 6m.on the second day he turns after 10km. On the third day he turns after 14km.

1.after how many kilometres does he turn on the 7th day

I keep seeing these "an athlete prepares for the Comrades" questions.

What does that even mean????

Did you mean "on the first day he turns after 6 km ?. I will assume that
so you have an AS, where a = 6, d = 4
term(7) = a + 6d
= 6 + 6(4) = 30

on the 7th day "he turns after" 30 km

You know that by just looking at the bot's answer that it must be
wrong, the distances after he turns would be
6 , 10, 14 , ....
the bot's answer of 28 doesn't even fit that pattern.

On the 7th day, he turns after 28km.