How many nucleotides adenine (A), thymine (T), guanine (G) and cytosine (C) are in a DNA fragment if 1200

How many nucleotides adenine (A), thymine (T), guanine (G) and cytosine (C) are in a DNA fragment if 1200 cytosine nucleotides are found in it, which is 20% of the total number of nucleotides in this DNA fragment?

By the principle of complementarity, the amount of adenine is equal to the amount of thymine, and the amount of cytosine is equal to the amount of guanine. According to the condition, cytosine is 20%, and this is (20 * 1200) / 100 = 240 nucleotides, which means guanine is also 20% and 240 nucleotides. Adenine with thymine accounts for 60%, this is (60 * 1200) / 100 = 720 nucleotides, which means that thymine is 360 nucleotides and adenine is 360.