SOLUTION: Maria, an experineced shipping clerk, can fill a certain order in 3 hours. tom a new clerk, needs 4 hours to do the same job. working together, how long will it take them to fill t

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Maria, an experineced shipping clerk, can fill a certain order in 3 hours. tom a new clerk, needs 4 hours to do the same job. working together, how long will it take them to fill t      Log On


   

Question 795644: Maria, an experineced shipping clerk, can fill a certain order in 3 hours. tom a new clerk, needs 4 hours to do the same job. working together, how long will it take them to fill the order?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Add their rates of working
Maria's rate:
( 1 order filled ) / ( 3 hrs )
Tom's rate:
( 1 order filled ) / ( 4 hrs )
----------------------
Let +t+ = time in hrs for them to
fill 1 order working together
----------------------
+1%2F3+%2B+1%2F4+=+1%2Ft+
Multiply both sides by +12t+
+4t+%2B+3t+=+12+
+7t+=+12+
+t+=+1.714+
+.714%2A60+=+43+
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It will take them 1 hr and 43 min working together
check answer:
+1%2F3+%2B+1%2F4+=+1%2Ft+
+1%2F3+%2B+1%2F4+=+1%2F1.714+
+.333+%2B+.25+=+.58333+
+.58333+=+.58333+
OK