Respuesta :
 What we are going to do for this case is find the cost for each case:
 Cost to run the car before the mechanic worked on it:
 [tex](4) * (8) = 32 dollars (32) * (1/340) = 0.09 dollars / mile[/tex]
 Cost to run the car after the mechanic worked on it:
 [tex](4) * (7) = 28 dollars (28) * (1/350) = 0.08 dollars / mile[/tex]
 The difference between both cases is:
 [tex]0.09 - 0.08 = 0.01 dollars / mile [/tex]
 Answer:
 It cost to run the car after the mechanic worked on it 0.01 $ / mile less than before the mechanic worked on it.
 Cost to run the car before the mechanic worked on it:
 [tex](4) * (8) = 32 dollars (32) * (1/340) = 0.09 dollars / mile[/tex]
 Cost to run the car after the mechanic worked on it:
 [tex](4) * (7) = 28 dollars (28) * (1/350) = 0.08 dollars / mile[/tex]
 The difference between both cases is:
 [tex]0.09 - 0.08 = 0.01 dollars / mile [/tex]
 Answer:
 It cost to run the car after the mechanic worked on it 0.01 $ / mile less than before the mechanic worked on it.