SOLUTION: One grocery clerk can stock a shelf in 45 min. A second clerk requires 25 min to stock the same shelf. How long would it take to stock the shelf if the two clerks worked together?

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Question 451512: One grocery clerk can stock a shelf in 45 min. A second clerk requires 25 min to stock the same shelf. How long would it take to stock the shelf if the two clerks worked together?
Found 2 solutions by nerdybill, pedjajov:
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
One grocery clerk can stock a shelf in 45 min. A second clerk requires 25 min to stock the same shelf. How long would it take to stock the shelf if the two clerks worked together?
.
Let x = time (minutes) it takes for both
then
x(1/45 + 1/25) = 1
x(25 + 45) = 1125
x(70) = 1125
x = 16.1 minutes

Answer by pedjajov(51) About Me  (Show Source):
You can put this solution on YOUR website!
First clerk finishes 1%2F45 of the shelf in one minute, while the second clerk finishes 1%2F25 of the shelf in a minute.
Together they would finish 1%2F45+%2B+1%2F25 of the shelf in a minute.
1%2F45+%2B+1%2F25 = 10%2F450+%2B+18%2F450 = 28%2F450
Now we have a proportion that they would finish 28%2F450 of the shelf in one minute and we have to find how long it would take them to finish a whole shelf:
28/450 : 1 = 1 : x
From here
x+=+450%2F28 = 16.07 minutes