Question 105512
Let x=# of students, and y=# of adults


You know that there are 215 people total. So the sum of the students and adults 
is 215. In other words, x plus y equals 215



So the first equation represents everyone who attended



Equation 1: {{{x+y=215}}}




Now since it's $0.50 a student, x students would generate {{{0.5x}}} dollars. Also since it's $2 per adult, y adults would generate {{{2y}}} dollars. So the sum of these two expressions would give the total revenue of  $250. In other words,  0.5x plus 2y equals 250 would be your second equation




So the second equation represents the total revenue generated from the two groups



Equation 2: {{{0.5x+2y=250}}}



Now just use elimination or substitution to solve for x and y