Question 674338
let {{{ r }}} = A's rate in still water ( no current )
Going downstream, his rate is {{{ r + 6 }}}
Going upstream, his rate is {{{ r - 6 }}}
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Going downstream,
{{{ 9 = ( r + 6 )*t[1] }}}
Going upstream,
{{{ 3 = ( r - 6 )*t[2] }}}
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You need to find {{{ t[1] + 1[2] }}}
{{{ t[1] = 9 / ( r + 6 ) }}}
{{{ t[2] = 3 / ( r - 6 ) }}}
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{{{ t[1] + t[2] = 9/( r + 6 ) + 3/( r - 6 ) }}}
I think you're missing his rate in still water
Can't solve without it.