Question

A company sells brass and steel machine parts.One shipment contains 3 brass and 10 steel parts and costs $48. A second shipment contains 7 brass and 4 steel parts and costs $54. Find the cost of each type of machine part.

Answer 1

Let
x--------------> brass cost
y--------------> steel cost
we know that
3x+10y=48
7x+4y=54 -------------------> multiply by -3/7----------> -3x-(12/7)y=-162/7

3x+10y=48
-3x-(12/7)y=-162/7
---------------------------
0x+8.29y=24.86-------------> y=3
3x+10y=48------> 3x+10*3=48----------> x=(48-30)/3=6

the answer is
brass machine parts cost $6
steel machine parts cost $ 3