System of equations, please help.
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Answer:
3.75*A + 2.50*D = 35
A + D = 12
A = 12 - D
3.75*(12-D) +2.5*D= 35
45 - 3.75D + 2.5D = 35
45 - 1.25D = 35 |-35
10 - 1.25D = 0 |+1.25D
10 = 1.25D | /1.25
8 = D
A+D=12
A+8=12 |-8
A=4
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