An alloy of tin is 15% tin and weighs 20 pounds. A second alloy is 10% tin How many pounds of the second alloy

must be added to the first to get a 12% muture?

500

30 pounds

Step-by-step explanation:

Amount of tin in first alloy + amount of tin in second alloy = amount of tin in mixture

0.15 (20) + 0.10 x = 0.12 (20 + x)

3 + 0.10 x = 2.4 + 0.12 x

0.6 = 0.02 x

x = 30