document.write( "Question 1134694: A tap fills a tank in 60 mins, another tap fills the same tank in 25 mins, and a third tap fills the same tank in 15 mins. How much time will those take if they run at the same time to fill this tank? \n" ); document.write( "

Algebra.Com's Answer #752154 by josmiceli(19441) $\"\"$ $\"About$

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Add their rates of filling, which is:
\n" ); document.write( "[ how much of the tank is filled ] / [ time to fill that much ]
\n" ); document.write( " $\"+1%2F1+\"$ means 1 tank filled in 1 hr
\n" ); document.write( "Let $\"+t+\"$ = time in hrs to fill the tank with all 3 open
\n" ); document.write( " $\"+1%2F60+%2B+1%2F25+%2B+1%2F15+=+1%2Ft+\"$ ( in minutes )
\n" ); document.write( " $\"+1%2F%2860%2F60%29+%2B+1%2F%2825%2F60%29+%2B+1%2F%2815%2F60%29+=+1%2Ft+\"$ ( in hrs )
\n" ); document.write( " $\"+5%2F5+%2B+1%2F%285%2F12%29+%2B+1%2F%283%2F12%29+=+1%2Ft+\"$
\n" ); document.write( " $\"+1+%2B+12%2F5+%2B+4+=+1%2Ft+\"$
\n" ); document.write( "Multiply both sides by $\"+5t+\"$
\n" ); document.write( " $\"+5t+%2B+12t+%2B+20t+=+5+\"$
\n" ); document.write( " $\"+37t+=+5+\"$
\n" ); document.write( " $\"+t+=+5%2F37+\"$ hrs
\n" ); document.write( "or
\n" ); document.write( " $\"+t+=+%285%2F37%29%2A60+\"$ min
\n" ); document.write( "----------------------------
\n" ); document.write( "check:
\n" ); document.write( " $\"+1+%2B+12%2F5+%2B+4+=+1%2F%285%2F37%29+\"$
\n" ); document.write( " $\"+5+%2B+12%2F5+=+37%2F5+\"$
\n" ); document.write( " $\"+25+%2B+12+=+37+\"$
\n" ); document.write( "OK
\n" ); document.write( " \n" ); document.write( "

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