Question

21. If 2, 3k - 1,8 are in A.P. then what is the value of k?​

Answer 1

Answer :

K = 2

Explanation :

If 2, (3k - 1) and 8 are in AP,their common difference would be equal

Now,

$\sf \: 8 - (3k - 1) = (3k - 1) - 2 \\ \\ \sf \: \implies \: 9 - 3k = 3k - 3 \\ \\ \sf \: \implies \cancel{3} \: ( 3 - k) = \cancel{3}(k - 1) \\ \\ \implies \: \sf \: 2k = 4 \\ \\ \implies \: \boxed{ \boxed{ \sf{k = 2}}}$

Answer 2

3K-1-2=3k-3

8-(3k-1)=9-3k

3k-3=9-3k
6k=12
K=2