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Your setup is INCORRECT.
A correct setup equation is
40x + 6*(1.5x) + 4*(2x) = 456.
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Comment from student: I made a typo. My 6(1.2x) should be 6(1.5x). Everything else is correct.
My response: A correct answer from your side should sound like THIS:
Thanks for your response and thanks for detecting/pointing my typo.