Question 1191386
x = number of main level tickets.
y = number of terrace level tickets.
your two equations are:
x + y = 16
69x + 39y = 714
multiply both sides of the first equation by 69 and leave the second equation as is to get:
69x + 69y = 1104
69x + 39y = 714
subtract the second equation from the first to get:
30y = 390
solve for y to get:
y = 13
solve for x from x + y = 16 to get:
x = 3
replace x and y with 3 and 13 in the original equations to get:
x + y = 16 becomes 3 + 13 = 16 which becomes 16 = 16.
69x + 39y = 714 becomes 207 + 507 = 714 which becomes 714 = 714.
this confirms the solution is correct.
your solution is that 3 main level tickets and 13 terrace level tickets.