u- amount of upper level tickets which cost 25$
m-amount of middle level tickets which cost 30$
b-amount of bottom level tickets which cost 35$
m+b=u and
m+b+u=49000 and
25u+30m+35b=1419500
putting u from first equation to the second
2u=49000
u=24500 - seats in upper level
m+b=24500 so m=24500-b
25*24500+30(24500-b)+35b=1419500
612500+735000-30b+35b=1419500
1347500+5b=1419500
5b=72000 /:5
b=14400 amount of seads in bottom level