Question 1077415
The way they got this equation is the following:
Let {{{ d }}} = the one-way distance fromhouse to stadium
(1) {{{ d = 50*( t-1 ) }}}
(2) {{{ d = 30t }}}
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Therefore:
{{{ 50*( t-1 ) = 30t }}}
{{{ 50t - 50 = 30t }}}
{{{ 20t = 50 }}}
{{{ t = 2.5 }}} hrs
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Plug this result back into (1) or (2)
(2) {{{ d = 30t }}}
(2) {{{ d = 30*2.5 }}}
(2) {{{ d = 75 }}} mi
The distance, in miles, from Bill’s 
house to the baseball stadium is 75 mi
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check:
(1) {{{ d = 50*( t-1 ) }}}
(1) {{{ d = 50*( 2.5-1 ) }}}
(1) {{{ d = 50*1.5 }}}
(1) {{{ d = 75 }}} mi
OK