SOLUTION: During one month, a homeowner used 500 units of electricity and 100 units of gas for a total cost of 352.00. the next month, 400 units of electricity and 150 units of gas were used

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Question 430100: During one month, a homeowner used 500 units of electricity and 100 units of gas for a total cost of 352.00. the next month, 400 units of electricity and 150 units of gas were used for a total cost of 304.00. Find the cost per unit of gas
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!

gas cost x
electricity cost y
100x+500y=352 .............1
150x+400y=304 .............2
Eliminate y
multiply (1)by -4
Multiply (2) by 5
-400x-2000y=-1408
750x+2000y=1520
Add the two equations
350x= 112
/350
x=0.32 gas unit cost
plug value of x in (1)
100x+500y=352
32+500y=352
500y=352-32
500y=320
y=0.64 electricity cost
CHECK

100 x + 500 y = 352
32 320 = 352
352 = 352