If a DNA sample contains 30% Cytosine, what percentage of Thymine does it contain?

In DNA, the amount of cytosine (C) is always equal to the amount of guanine (G), due to the base-pairing rules (C pairs with G). Similarly, the amount of adenine (A) is always equal to the amount of thymine (T) (A pairs with T).

Given that the DNA sample contains 30% cytosine, it necessarily contains 30% guanine as well. This means that together, cytosine and guanine make up 60% of the DNA sample (30% C + 30% G).

Since the total percentage of all four bases (adenine, thymine, cytosine, and guanine) must equal 100%, the remaining percentage is for adenine and thymine combined, which is 40% (100% - 60%). Because adenine and thymine are in equal proportions, each must account for half of the remaining 40%. Therefore, adenine contributes 20% and thymine, correspondingly, also contributes 20% to the DNA sample.

This establishes that the DNA sample containing 30% cytosine must also contain 20% thymine, confirming that this is indeed the