If a sample of white gold alloy contains 60 percent by mass of gold while the remaining is platinum, then the alloy would contain 40 percent by mass of platinum. Percentage
by mass is the amount in mass units of a component in a mixture per 100 unit if mass of the
total mixture. We are given the amount of gold available, this represents the 60 percent of the alloy. We calculate for the amount of platinum needed as follows:
Percent of platinum = mass of platinum / mass of gold + mass of platinum
0.40 = mass of platinum / 175 g + mass of platinum
mass of platinum = 117 g
