For an alloy that consists of $75\mathrm{.}8g$ copper, $103\mathrm{.}7g$ zinc, and $5\mathrm{.}4g$ lead, what are the concentrations of $($a$)Cu,($b$)Zn,$ and $($c$)Pb$

in weight percent? The atomic weights of $Cu,Zn,$ and $Pb$ are $63\mathrm{.}54,65\mathrm{.}39,$ and $207\mathrm{.}2\frac{g}{m}ol,$ respectively. What is the composition, in atom percent, of an alloy that contains a$)75\mathrm{.}8$ lbm of silver, b$)103\mathrm{.}7$lbm of gold, and c$)5\mathrm{.}4$ lbm of Cu$?$ Assume that the atomic weights for silver, gold and copper are, respectively, $63\mathrm{.}54,65\mathrm{.}39$ and $207\mathrm{.}2$ g$/$mol$.$ Round off your answers to $3$ significant digits.