Question 893822
This is a linear relation
If you let {{{ d }}} = km traveled,
then the slope would be {{{ .5 }}}
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Let {{{ C }}} = the total cost in dollars
{{{ C = .5d + 500 }}}
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The gradient is the slope, {{{ .5 }}}
This this the rate at which you pay 
for each km driven.
$.5 times 1 km driven = $0.50