A high school drama department sold 238 tickets for their performance. o   An adult ticket cost $6.75.
o   A student ticket cost $3.50.
o   The high school drama department collected $1,252.25 in ticket sales.
How many student tickets were sold? 

Let x = number of student tickets
Ley y = number of nonstudent tickets

then we know that the total number of tickets is 537

so

x + y = 537

if we multiply the cost of a ticket by the number of tickets we can also get the total $

3.2x + 5.9y = 2185.5

now we have two equations and two unknowns and we can find the value for these unknowns

lets use substitution

x + y = 537 that means that x = 537-y

substitute this value in the second equation

3.2(537-y) + 5.9y = 2185.5

1718.4 - 3.2y +5.9y = 2185.5

1718.4 + 2.7y = 2185.5

2.7y = 2185.5 - 1718.4

2.7y = 467.1

y = 173

x + y =537

x + 173 = 537

x = 364