<PRE><B>Question 207010</B>
Let the amount of local miles traveled during the 1st week of October be L


Then the total amount of miles traveled in that 1st week is 180 + L


Then the amount of gas used to travel locally is {{{L/20}}}, since the car 

gives 20 miles per gallon, locally 


And, the total amount of gas utilized that week was:  {{{L/20 + 180/30}}} or {{{L/20 + 6}}}


Therefore, (total amount of miles traveled) / (total amount of gas utilized) = average weekly consumption, or: {{{(180 + L)/(L/20 + 6)=26}}} = {{{(180 + L)/((L + 120)/20)=26}}} = {{{180 + L = (26L + 3120)/20}}} 


3600 + 20L = 26L + 3120


-6L = - 480


L = 80


Therefore, the amount of local miles driven was: {{{highlight_green(80)}}}


Check:

Total miles driven in 1 st week = 260 (180 highway + 80 local)

Total gas utilized in 1st week: 10 (6 highway + 4 local)

It follows that average gas consumption for 1st week was {{{260/10}}}. or 26


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