Question 918999

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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Let additional time be T
Then: {{{(4/5)/(1/5) = 3/T}}}
{{{T(4/5) = 3(1/5)}}} ------ Cross-multiplying
{{{4T/5 = 3/5}}}
4T = 3 ------ Denominators are equal, and so are the numerators 
T, or additional time taken to fill tub = {{{highlight_green(3/4)}}} min, or {{{highlight_green(.75)}}} min