SOLUTION: Seymour Blossoms and Pete Moss plant flowers in a botanical garden. Working by himself it takes Seymour 7 hours to plant the flowers and it takes Pete 3 hours to plant the flowers

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Question 1104894: Seymour Blossoms and Pete Moss plant flowers in a botanical garden. Working by himself it takes Seymour 7 hours to plant the flowers and it takes Pete 3 hours to plant the flowers when he works by himself. How long does it take them to plant the flowers if they work together?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Add their rates of planting to get their
rate planting together
SB's rate is [ 1 job ] / [ 7 hrs ]
PM's rate is [ 1 job ] / [ 3 hrs ]
Let their rate working together =
+1%2Ft+ where t = time in hrs
---------------------------------
+1%2F7+%2B+1%2F3+=+1%2Ft+
Multiply both sides by +3%2A7t+
+3t+%2B+7t+=+3%2A7+
+10t+=+21+
+t+=+2.1+ hrs
+.1%2A60+=+6+ min
----------------------
working together, it will take them 2 hrs and 6 mins
----------------------
check:
+1%2F70+%2B+1%2F30+=+1%2F21+
+.014286+%2B+.033333+=+.047619+
+.047619+=+.047619+
OK