A DNA-like molecule is isolated from the frozen remains of alien life-forms found beneath the Martian North polar ice cap. The molecule is a double stranded polymer whose monomeric subunits are composed of glycerol, phosphate and nitrogenous bases, of which four kinds were found. The bases in this "glyceronucleic acid" are symbolized as B, D, H, and U. The monomers are linked through phospodiester bonds and the bases form hydrogen bonds between the strands according to the following rules; For every B, there are twice as many Ds; for every H, there are twice as many Us. If the molecule contains 30% Ds, what do you expect is the percentage of Us?