Intermediate algebra, concepts and graphs
posted by Lisa .
Tickets for a school event were $2.50 for students and $3.50 for parents. If a total of 80 tickets were sold for $234.00, how many students and parent tickets were sold?

st = Number of students
pr = Number of parents
pr = 80  st
2.5 * st + 3.5 * pr = 234
2.5 * st + 3.5 * ( 80  st ) = 234
2.5 st + 3.5 * 80  3.5 St = 234
2.5 st + 280  3.5 st = 234
280  st = 234 Add st to both sides
280  st + st = 234 + st
280 = 234 + st Subtract 234 to both sides
280  234 = 234 + st  234
46 = st
st = 46
pr = 80  46 = 34
46 students and 34 parents
Proof :
2.5 $ * 46 + 3.5 $ * 34 = 115 $ + 119 $ = 234 $