Mendeleev was the first scientist to arrange the element in such a periodic order but there was a mistake that he arranged in increasing order of mass.
Today we use the periodic table given by Henry Mosley where atomic no is first priority
Thymine pairs with adenine. If thymine is 15% then so would adenine be 15%. That leaves the reaminder to be 70%. Cytosine pairs with guanine, thereby, they would each be 35%.
