In a DNA molecule 28% of all bases found were Adenine. What are the remaining bases and their percentages in this molecule?

first remember your base pairs: Adenine binds to Thymine and then Cytosine binds to Guanine. So if 28% are Adenine then 28% must also be Thymine. 28+28= 56% so 100-56 gives you the remaining percentage which = 44% this must be split between Cytosine and Guanine which therefor are 22% each.