Question 1130663
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<pre>
Let x be the number of students and y be the number of others.


 x +  y = 300    (1)
2x + 3y = 670    (2)


To solve the system, multiply eq(1) by 2 (both sides). Keep eq(2) as is.


2x + 2y = 600    (1')
2x + 3y = 670    (2')


Subtract eq(1') from eq(2')  (both sides).  You will get


     3y - 2y = 670-600

        y    =  70.


Then from eq(1),  x = 300-70 = 230.


<U>Answer</U>.  230 students tickets were sold.
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Solved.