Let L be the low copper alloy and H be the high copper alloy.
We need 0.15L + 0.60H = 0.42 and L + H = 100
L=100 - H
Substituting this into the second equation for L, we get:
0.15(100-H) + 0.60H = 0.42(H+L)
15 - 0.15H + 0.60H = 0.42(H+100-H)
15 + 0.45H = 0.42(100)
0.45H = 42 - 15 = 27
H = 27/.45 = 60 lbs
Back substitution, L = 40 lbs.
This is a system of equation:
7y - 5x = 31
x = 4 - 2y
Plug in 4 - 2y for x
7y - 5(4 - 2y) = 31
Distribute -5 to both 4 and -2y
7y - 20 + 10y = 31
Simplify
17y - 20 = 31
Isolate the y. Note the equal sign. What you do to one side you do to the other. Do the opposite of PEMDAS.
Add 20 to both sides
17y - 20 (+20) = 31 (+20)
17y = 51
Divide 17 from both sides to isolate the y
17y/17 = 51/17
y = 51/17 or 3
y = 3
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Plug in 3 for y in one of the equations.
x=4−2y
x = 4 - 2(3)
Simplify.
x = 4 - 6
x = -2
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x = -2, y = 3 is your answer, or B)
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hope this helps
Answer:
12 pieces per person
Step-by-step explanation:
Since you are splitting 108 pieces between 9 people the equation is 108/9 which is equal to 12, making the amount of candy each person would get, 12.
The value of the the digit in the tenths place is 9...19.9
