Question 1114278
.
<pre>
4x + 7*(5000-x) = 21500    ("money" equation)


4x + 35000 - 7x = 21500


-3x = 21500 - 35000 = -13500   ====>  x = {{{(-13500)/(-3)}}} = 4500.


<U>Answer</U>.  4500 student tickets and 5000-4500 = 500 non-student tickets were sold.


<U>Check</U>.   4*4500 + 7*500 = 21500 dollars.   ! Correct !
</pre>

Solved.


--------------
It is a standard ticket problem.


Read the lessons

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/coordinate/lessons/Using-systems-of-equations-to-solve-problems-on-Tickets.lesson>Using systems of equations to solve problems on tickets</A> 

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/coordinate/lessons/Three-methods-for-solving-standard-typical-problem-on-tickets.lesson>Three methods for solving standard (typical) problems on tickets</A>

in this site.


Learn from these lessons on how to solve such problems once for all.


Also, &nbsp;you have this free of charge online textbook in ALGEBRA-I in this site

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson>ALGEBRA-I - YOUR ONLINE TEXTBOOK</A>.


The referred lessons are the part of this online textbook under the topic "<U>Systems of two linear equations in two unknowns</U>".