The word equation for this problem is portion of job

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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.

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