Which function has an inverse that is also a function?
{(–1, –2), (0, 4), (1, 3), (5, 14), (7, 4)}
{(–1, 2), (0, 4), (1, 5), (5, 4), (7, 2)}
{(–1, 3), (0, 4), (1, 14), (5, 6), (7, 2)}
{(–1, 4), (0, 4), (1, 2), (5, 3), (7, 1)}

A function will not have any repeating x values...it can have repeating y values, just not the x ones. The inverse of these points can be found by just switching the x and y values. Example : (2,3)...inverse is (3,2)

(-1,3), (0,4), (1,14), (5,6), (7,2)this has no repeating x values, so it is a function.
Now look at its inverse :
(3,-1) , (4,0), (14,1), (6,5), (2,7)...this has no repeating x values, so it is a function

so ur answer is : C

10 will be the number of adult tickets and 11 will be the number of children tickets. i hope i could ! good luck : )