Among the given alloys, How many alloys have the %age at Cu maximum as compare to other metals present in that alloy.
Solder, Brass, Bronze, Gun-metal, stainless steel, Invar

Three Brass, Bronze and Gun-metal alloys have the %age at Cu maximum as compare to other metals present in that alloy.
Solder alloy contains 1 to 4 % Cu.
Brass contains 60 to 90 % copper.
Bronze contains 55 to 92 % copper.
Gun-metal contains 80 - 90% copper.
stainless steel, is a steel alloy with a minimum of 10.5% chromium content by mass. It does not contain copper
Invar is a nickel iron alloy and does not contain copper.