Question 254286
I suspect you mean, "Please, include the work."
The work is not extra.
But I am not going to solve it for you.
I will set up the equation and you get to have all the fun
l=lower level tickets sold
u=upper level tickets sold
20.70l+6.75u=220050
u+l=14000
Have fun at the concert. Who's playing?
ok you talked me into it.

9000 =l