Question 804576
first, you need to understand the question by writing down what you know.
so lets begin:
- the cost of a movie for an adult = 180. lets call adult A for short
- the cost of a movie for a senior = 144. lets call seniors S
- on this particular day, 310 people watched a movie but we don't know how many of them were adults or seniors. But we know for sure that 310 people were made up of A + S. A number of adults and S number of seniors. 
- Now we can form our first linear equation; A + S = 310
- we also know that the receipts for this day totaled 54,540. since we know how much a ticket was for adults and seniors we can form our second equation; therefore 180A + 144S = 54,540
- we now have 2 simultaneous equations which we can solve using the substitution method.

   A + S = 310
180A + 144S = 54540

1st) express S as a function of A; S = 310 - A
2nd) substitute our equation for S into equation 2; 180A + 144(310-A) = 54540
3rd) simplify; 
4th) you'll find that A = 275
5th) plug A into equation 1 like so; 275 + S = 310 therefore S = 35

check your answers does 180(275) + 144(35) = 54540 ? if so you're done