Calculate the relative number of atoms of each element contained in each of the following alloys:

(a) Rose metal, which is a low-melting-point alloy used to solder decorative ironworks and is often 28% lead and 22% tin by mass in bismuth;

(b) duralumin AA2024, an alloy that hardens aluminum for use in aircraft and is 4.4% copper, 1.5% magnesium, and 0.6% manganese in aluminum.