Question 934258
Sum of the rates is the combined fill rate of both faucets.  TUB per HOUR units.


{{{1/(1/2)+1/1}}}, rate of hot faucet plus rate of cold faucet.


{{{2+1}}}


{{{3}}}--------TUBS per HOUR




You want, how many hours per 1 tub, which means {{{3*tubs/(1*hour)}}} must be used as {{{1*hour/(3*tubs)}}}


{{{1/3}}} hour to fill 1 tub.
This is 20 minutes to fill 1 tub.