You decide to build a circuit for an electronic buzzer. Digging
around, you found some solder (composition 80wt% Pb, 20% Sn) and a
soldering iron. Attempting the soldering process revealed that the
solder doesn’t melt, no matter how long you put the soldering iron
on it. Apparently, your soldering iron has a maximum temperature of
only 225 °C. If you have 60 grams of the 80/20 solder, how much tin
would you need to add in order to solder the circuit? Assume
soldering requires complete melting of the alloy.