Question 865857
Add their rates of filling to get
their rate of filling together
A's rate:
( 1 tank filled ) / ( t hrs )
B's rate:
( 1 tank filled ) / ( 7 hrs )
Rate for A and B together:
( 1 tank filled ) / ( 2 hrs )
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{{{ 1/t + 1/7 = 1/2 }}}
Multiply both sides by {{{ 14t }}}
{{{ 14 + 2t = 7t }}}
{{{ 5t = 14 }}}
{{{ t = 14/5 }}}
{{{ t = 2.8 }}} hrs
{{{ .8*60 = 48 }}}
Pipe A alone fills the tank in
2 hrs 48 min