In figure 12-8, the percentage of guanine would

The correct answer is- 20%

As per the given table in the question, percentage of Adenine (A) is 30%, which means that percentage of Thymine (T) would also be 30%. This is in accordance with the Chargaff's rule (Adenine amount is equivalent to Thymine and amount of Guanine is equal to Cytosine amount in DNA).

Therefore, out of the remaining 40% (60% is fulfilled by A and T), 20% is Guanine and 20% is Cytosine.

Thus, percentage of Guanine is 20%.