The repair bill totaled $800 for labor (L) and parts (P). The labor cost was three times the cost of the parts. What did the parts cost?
Total = 800 = labor (L) + parts (P) (1)
labor (L) = 3 X parts (P)
L= 3 x P
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Replacing Lin terms of P in the original expression 1 of the total
800 = 3 x P + P
4P = 800
P = 200
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The parts cost $200