Question

A pound of tin is worth $2 more than a pound of copper. Three pounds of tin are mixed with 7 pounds of copper to make bronze that sells for $3.85 per pound. How much is a pound of tin worth

Answer 1

3 pounds of tin = 3(c+2) dollars
7 pounds of copper = 7 c dollars

10 pounds of bronze = 38.50 dollars

so
7 c + 3 c + 6 = 38.5
c = 3.25 dollars per pound for copper
so
c+2 = 5.25 dollars per pound for tin

Answer 2

cost of pound of copper ---- x
cost of pound of tin -------- x+2

3(x + 2) + 7x = 10(3.85)
3x + 6 + 7x = 38.5
10x = 32.5
x = 3.25

copper sells for $3.25 per pound, and tin sells for $5.25 per pound