The given series is in the below pattern ,
First series :-
First term = 12
Second term = First term × 2 + 2
⇒ Second term = 12 × 2 + 2 = 26
Third term = Second term ÷ 2 - 2
⇒ Third term = 26 ÷ 2 - 2 = 11
similarly , we can find the all others terms .
........... and so on.
Second series :-
First term = 7
Second term = First term × 2 + 2
⇒ Second term = 7 × 2 + 2 = 16
Third term = Second term ÷ 2 - 2
⇒ Third term = 16 ÷ 2 - 2 = 6
Fourth term = Third term × 3 + 3
⇒ Fourth term = 6 × 3 + 3 = 21
Hence , the place value of ( c ) is 21.