Question 404761
A pound of tin is worth $2 more than a pound of copper. 
Seven pounds of tin are mixed with 3 pounds of copper to make bronze that sells for $4.45 per pound.
 How much is a pound of tin worth?
:
Let t = cost of 1 lb of tin
then
(t-2) = cost of 1 lb of copper
:

7t + 3(t-2) = 4.45(7 + 3)
7t + 3t - 6 = 4.45(10)
7t + 3t = 44.5 + 6
10t = 50.5
t = {{{50.5/10}}}
t = $5.05 for a pound of tin
:
:
Check this
7(5.05) + 3(3.05) = 4.45(10)
35.35 + 9.15 = 44.50; confirms our solution of t = 5.05