Unformatted text preview: From the figure it looks like we’ve got the following word equation. æ Distance ö æ Distance ö
100 + ç
÷=ç
÷
è of Boat B ø è of Boat A ø
Upon plugging in the standard formula for the distance gives, æ Rate of ö æ Time of ö æ Rate of ö æ Time of ö
100 + ç
÷ç
÷=ç
÷ç
÷
è Boat B ø è Boat B ø è Boat A ø è Boat A ø
For this problem we know that the time each is 5 hours and we know that the rate of Boat A is 2r
and the rate of Boat B is r. Plugging these into the work equation and solving gives, 100 + ( r ) ( 5 ) = ( 2r ) ( 5 )
100 + 5r = 10r
100 = 5r
20 = r So, the slower boat is moving at 20 mph and the faster boat is moving at 40 mpg (twice as fast).
Work/Rate Problems
These problems are actually variants of the Distance/Rate problems that we just got done
working. The standard equation that will be needed for these problems is, æ Portion of job ö æ Work ö æ Time Spent ö
ç
÷=ç
÷´ç
÷
è done in given time ø è Rate ø è Working ø
As you can see this formula i...
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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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