What will be the composition of the second strand of DNA if the first contains 18% guanine, 30% adenine and 20% thymine?

The DNA chain contains 4 nucleotides guanine, adenine, thymine and cytosine. In the first chain, guanine is 18%, adenine is 30%, thymine is 20%, which means cytosine is 32% (100% -18% -30% -20% = 32%). Using the principle of complementarity, the exact coincidence of pairs of nitrogenous bases (adenine-thymine, guanine-cytosine), we get the result for the second chain. Guanine 32%, adenine 20%, thymine 30%, cytosine 18%.