SOLUTION: It takes Addy 40 minutes longer than her mother to wrap gifts. Working together they can wrap gifts in 20 minutes. How long would it take Addy by herself?
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Question 1013531: It takes Addy 40 minutes longer than her mother to wrap gifts. Working together they can wrap gifts in 20 minutes. How long would it take Addy by herself? Answer by fractalier(6550) (Show Source):
You can put this solution on YOUR website! Call her mother's time, t. Her time is t+40. The setup looks like this:
20/t + 20/(t+40) = 1
Multiply by t(t+40) and get
20(t+40) + 20t = t(t+40)
40t + 800 = t^2 + 40t
so that
t^2 = 800
t = 28.28 minutes (that is mom's time)
Addy's time is 40 more, or 68.28 minutes.