Answer: A = 27,500, B = 14,200, C = 13,300
Step-by-step explanation:
A = B + C
55,000 = A + B + C
30A + 24B + 18C = 1,405,200
Substitute #2 with A from #1
55,000 = B + C + B + C or 2B + 2C
Now substitute A for #3
30(B + C) + 24B + 18C = 1,405,200
30B + 30C + 24B + 18C = 1,405,200
54B + 48C = 1,405,200
Now multiply are new #2 equation by -24
(2B + 2C = 55,000)*-24
-48B + -48C = -1,320,000
Combine this equation to our new #3
[-48B + (-48C) = -1,320,000] + [54B + 48C = 1,405,200]
6B = 85,200
B = 14,200
Now that we got B we have to continue...
Substitute B in our new #2
2(14,200) + 2C = 55,000
Solve.
28,400 + 2c = 55,000
-28,400
2c = 26,600
C = 13,300
Now we can use #1
A + 14,200 + 13,300 = 55,000
A + 27,500 = 55,000
-27,500
A = 27,500
(There's also a much simpler way... Divide 55,000 in half to get A automatically.)