Question 1161109
.
<pre>


If you just know what is the systems of equations, then you can write, based on the condition


    x + y = 11302     (1)

    x - y =  2854     (2)

----------------------------------


Now add the equations, and you will get


    2x    = 11302 + 2854 = 14156;  hence,  x = 14156/2 = 7078.


<U>ANSWER</U>.  The longer river length is  7078 km;  The other river is  7078 - 2854 = 4224 km.
</pre>

Solved.


-----


If you don't know what is the system of equations, &nbsp;you may solve the problem by different way.



<pre>
Longer river length + other river length = 11302

    x               +    (x - 2854)      = 11302


    2x                                   = 11302 + 2854 = 14156

     x                                                  = 14156/2 = 7078 km


obtaining the same answer.
</pre>


Solved by two ways, &nbsp;to provide you the best knowledge.



-----------------


Regarding the method of solution with system of equation, &nbsp;know that this system is SIMPLEST of this kind.


To gain an experience solving such systems &nbsp;(and such problems), &nbsp;see the lesson

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/coordinate/lessons/Word-problems-that-lead-to-a-simple-system-of-two-equations-in--wo-unknowns.lesson>Word problems that lead to a simple system of two equations in two unknowns</A> 

in this site.