Answer:
32%
Step-by-step explanation:
According to Chargaff in his complementary base pairing rule, he stated that the proportion of purine and pyrimidine bases is equal to 100%
That is, A + T + G + C = 100%
Where A=T and G=C i.e the proportion of each base pair is equal.
Hence, if the Guanine content is 18%, it means the Cytosine content of that DNA molecule must also be 18%. Therefore:
18 + 18 + A + T = 100
A + T = 100 - 36
A + T = 64
If the sum proportion of Adenine and Thymine is 64% and each must contain equal proportions, A or T = 64/2 = 32
Hence, Adenine contains 32%, likewise Thymine.