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Example 8.84 from Elementary Algebra, 8.8 Solve Uniform Motion and Work Applications
Solve Uniform Motion and Work Applications: example 8.84
The weekly gossip magazine has a big story about the Princess’ baby and the editor wants the magazine to be printed as soon as possible. She has asked the printer to run an extra printing press to get the printing done more quickly. Press #1 takes 6 hours to do the job and Press #2 takes 12 hours to do the job. How long will it take the printer to get the magazine printed with both presses running together?
Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.
Solution
This is a work problem. A chart will help us organize the information.
Let the number of hours needed to complete the job together. Enter the hours per job for Press #1, Press #2 and when they work together.
If a job on Press #1 takes 6 hours, then in 1 hour of the job is completed.
Similarly find the part of the job completed/hours for Press #2 and when they both work together.Write a word sentence. The part completed by Press #1 plus the part completed by Press #2 equals the amount completed together. Translate to an equation. Solve. Multiply by the LCD, . Simplify. When both presses are running it takes 4 hours to do the job.
Your turn
The book's Try It right after this example: same idea, new numbers. Only the answer is given.
One gardener can mow a golf course in 4 hours, while another gardener can mow the same golf course in 6 hours. How long would it take if the two gardeners worked together to mow the golf course?
How did it go?