If 7 is transformed into 13 and 11 is changed to 21 then what does 16 become?

Question

 5  11   6   9
13  18  11  20
21  25  16   ? 

Answer 1

i.e. 7 x 2 – 1 = 14 – 1 = 13
Also 11 x 2 – 1 = 22 – 1 = 21
So to find resultant number for 16 we calculate;
16 x 2 – 1 = 32 – 1 = 31
Answer = 31.

Answer 2

16*2=32-1=31
Answer 31

Answer 3

7 * 2 - 1 = 14 - 1 = 13
11* 2 - 1 = 22 - 1 = 21
Then,
16 * 2 -1 = 32 - 1 = 31
The answer is 31

Answer 4

7=13
11=21

now 16=11+7-2

then 16 will be transformed into 13(instead of 7)+21(instead of 11)-2=32
then 16 is transformed into 32