Precalculus: Mathematics for Calculus, 7th Edition

Published by Brooks Cole
ISBN 10: 1305071751
ISBN 13: 978-1-30507-175-9

Chapter 1 - Section 1.7 - Modeling with Equations - 1.7 Exercises - Page 76: 32

Answer

Assistant: 35 hours Plumber: 70 hours

Work Step by Step

They charge 25 for an hour of assistants work and 45 for plumbers equivalent. Assistant worked certain amount of hours (x) and plumber twice as much (2x). The charge on the final bill was 4025. 45$\times$2x+25x=4025 90x+25x=4025 115x=4025 x=35 And plumber did twice as much so 2$\times $35=70 hours
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