Question 344410
Let A be the amount of copper and let B be the amount of tin.
Total weight equation:
1.{{{A+B=15.3}}}
Total cost equation:
{{{8.9A+9.5B=15.3(9.1)}}}
2.{{{8.9A+9.5B=139.23}}}
From eq. 1,
{{{A=15.3-B}}}
Substitute into eq. 2,
{{{8.9(15.3-B)+9.5B=139.23}}}
{{{136.17-8.9B+9.5B=139.23}}}
{{{0.6B=3.06}}}
{{{highlight(B=5.1)}}}kg
Then from eq. 1,
{{{A+5.1=15.3}}}
{{{highlight(A=10.2)}}}kg