word problem doing slop intersection solving equations with elimination

Question

suppose that there are two types of tickets to a show : advanced and same-day. the combined cost of one advanced ticket and one same-day ticket is $50. for one performance,20 advance tickets and 40 same-day tickets were sold. the total amount paid for the ticket was $1700.what was the price of each kind of tickets?

Answer 1

a + s = 50

20a+ 40s = 1700

20a + 20s= 20(50)

40s-20s = 1700-1000

20s = 700

s = 700/20 = 35 same day tickets

a = 50-35 = 15 advance ticket

20(15)+40(35)

= 300 +1400

=1700