Question 806819
Plot the distance in km on the horizontal axis
Plot the fare for the trip on the vertical axis
Let {{{ d }}} = distance in km
Let {{{ c }}} = fare for the trip
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Use the general point slope formula
{{{ ( c - 3.75 ) / ( d - 5 ) = ( 6.75 - 3.75 ) / ( 10 - 5 ) }}}
{{{ ( c - 3.75 ) / ( d - 5 ) = 3 / 5 }}}
Multiply both sides by {{{ 5*( d-5 ) }}}
{{{ 5*( c - 3.75 ) = 3*( d-5 ) }}}
{{{ 5c - 18.75 = 3d - 15 }}}
{{{ 5c = 3d + 3.75 }}}
{{{ c = .6d + .75 }}} 
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check answer:
{{{ c = .6*5 + .75 }}}
{{{ c = 3.75 }}} 
and
{{{ c = .6*10 + .75 }}}
{{{ c = 6.75 }}}
OK
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{{{ d = 32 }}} km
{{{ c = .6*32 + .75 }}}
{{{ c = 19.2 + .75 }}}
{{{ c = 19.95 }}}
A 32 km trip costs $19.95

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