First, break down what they are saying and write all statements as equations:


1. There are two types of seats: $25 ones and $50 dollar ones. Assign variables for these types of seats


X = $25 seats, Y = $42 seats


2. The amount of seats sold (number of tickets) is 50.


X + Y = 50


3. Total money raised is $1590.


25X + 42Y = 1590 ($25*number of X seats PLUS $42*number of Y seats = total amount of money made)


This is a system of equations. Since you have 2 unknowns you need two equations to solve them, and that is what we have:


X + Y = 50
25X + 42Y = 1590


Isolate any variable from one equation, and insert it into the other:


X = 50 - Y                          [isolating X in first equation]
25(50-Y) + 42Y = 1590        [inserting it into second equation]
1250 - 25Y + 42Y = 1590     [solving for Y]
17Y = 340
Y = 20


So 20 of the $42 seats were sold. Now put that answer into either equation to find how many $25 seats were sold (X seats).


X + 20 = 50
X = 30


To Check:


20+30 does equal 50 and:


25(30) + 20(42) = 1590 ???
750 + 840 = 1590 ???
1590 = 1590  YES


Hope that helps :)