Question 918999: If it takes 3 minutes to fill 4/5 of a tub how much longer will it take to fill the rest? Found 3 solutions by josmiceli, Alan3354, MathTherapy:Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website! There is of the tub left to fill
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The rate of filling stays the same, so
rate =
and, also
rate =
so, I can say:
It takes 3/4 of a minute to fill the rest
check:
I can now say that the rate is:
This is just ( rate ) = ( rate )
OK
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website! If it takes 3 minutes to fill 4/5 of a tub how much longer will it take to fill the rest?
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4/5 in 3 mins --> 4/15 in 1 minute
Fill rate = 4/15 of a tub/min
min/tub = 1/(tub/min) = 1/(4/15) = 15/4 minutes
= 3.75 minutes
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or
3/0.8 = t/1
0.8t = 3
t = 3/0.8
t = 3.75 minutes
Let additional time be T
Then: ------ Cross-multiplying
4T = 3 ------ Denominators are equal, and so are the numerators
T, or additional time taken to fill tub = min, or min