Identifying amino acids produced using fixed proportions of nucleotide residues

A solution containing 80% cytosine and 20% uracil was used to make synthetic RNAs. A bacterial cell free system produced proteins using these mRNAs in the following proportions:

a) 4 times as many serine as leucine residues.

b) 16 times as many serine residues as phenylalanine residues.

c) 16 times as many proline residues to leucine residues.

Identify the amino acids formed.