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Unformatted text preview: equation to get these rates. æ Work ö æ Time Spent ö
1 Job = ç
÷´ç
÷
è Rate ø è Working ø
Let’s start with Machine A. 1 Job = ( Work Rate of A ) ´ ( 5 ) Þ Work Rate of A = 1
5 Þ Work Rate of B = 1
3 Now, Machine B. 1 Job = ( Work Rate of B ) ´ ( 3) Plugging these quantities into the main equation above gives the following equation that we need
to solve. 11
Multiplying both sides by 15
t + t =1
53
3t + 5t = 15
8t = 15
15
t = = 1.875 hours
8
So, it looks like it will take the two machines, working together, 1.875 hours to stuff a batch of
envelopes. Example 9 Mary can clean an office complex in 5 hours. Working together John and Mary can
clean the office complex in 3.5 hours. How long would it take John to clean the office complex
by himself?
Solution
Let t be the amount of time it would take John to clean the office complex by himself. The basic
word equation for this problem is, © 2007 Paul Dawkins 77 http://tutorial.math.lamar.edu/terms.aspx College Algebra æ Portion of job ö æ Portion of job ö
ç
÷+ç
÷ = 1 Job
è done by Mary ø è done by John ø
æ Work Rate öæ Time S...
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This note was uploaded on 06/06/2012 for the course ICT 4 taught by Professor Mrvinh during the Spring '12 term at Hanoi University of Technology.
 Spring '12
 MrVinh

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