What is the Percentage of Adenine in a Sample of Double-Stranded

Question

What is the percentage of adenine in a sample of double-stranded DNA containing 32% cytosine?
A)0%
B)18%
C)32%
D)68%

Accepted Answer

In double-stranded DNA, the amount of adenine (A) equals the amount of thymine (T), and the amount of cytosine (C) equals the amount of guanine (G). If cytosine is 32%, then guanine is also 32%. This leaves 36% for adenine and thymine combined, so adenine is 18%.