in triangle pqr and triangle xyz, PQ=XY. QR=YZ, ext angle PQM=ext angle XYN. Prove that triangle PQR congruent to triangle XYZ

Several paint mixtures are made by mixing blue paint and white paint. paint colors blue paint white paint mixture a 5 cups 12 cups mixture b 6 cups 6 cups mixture c 4 cups 12 cups mixture d 5 cups 6 cups which mixture has the highest ratio of blue paint to white paint