Question 1095983
If R is for fuel efficiency in miles per gallon;
V is for volume of fuel in gallons;
D is for distance in miles,
A useful formula is {{{RV=D}}}, or {{{R=D/V}}}.


<pre>
Let v be how many gallons used in highway driving.

                    FUEL EFFICIENCY    VOLUME      DISTANCE

CITY                  28               11-v        28(11-v)

HIGHWAY               33               v            33v

Totals                                 11             343
</pre>

{{{highlight_green(28(11-v)+33v=343)}}}-----basic equation to solve.

-

{{{308-28v+33v=343}}}
{{{5v=343-308}}}
{{{5v=35}}}
{{{v=7}}} and {{{11-v=4}}}.


City Miles,  {{{28*4=highlight(112)}}}
Highway Miles,  {{{33*7=highlight(231)}}}


-
You could assign a variable to one of the distances instead, and form an equation that way, using sum of the volumes.