Let x be the number of students

y be the number of non-students

since the ticket costs 240 for students and 360 for non and the total sales is 42,000 then you'll have the equation as:

240x + 360y = 42,000 ----equation 1

since you're provided with the data that there 250 more student tickets then you'll have

x = y + 250 ----equation 2

substituting equation 2 to equation 1

240x + 360y = 42,000

240(y+250) + 360y = 42,000

240y + 60000 + 360y = 42,000

240y + 360y = 42,000 - 60,000

600y = -18,000

**y = -30**

substitute to equation 2

x = -30 + 250

x = -30 + 250

__x = 220 __

x and y are 220 and -30 respectively.. might as well check your given data since it should have been that both x and y are of positive values since this deals with the number of persons.. but based on the given data above 220 and -30 are the values