In a DNA sample, 15% of the bases are thymine (T). What percentage of the bases in this sample are adenine (A)

In DNA, thymine binds to adenine, and cytosine binds to guanine. This means that there is an equal amount of thymine and adenine, and there is an equal amount of cytosine and guanine.

If there is 15% thymine, there should be 15% adenine.

Note that in real life, the percentage of bases won't be 100% equal.