Tickets to a movie cost $7.25 for adults and $5.50 for students. A group of friends purchased 8 tickets for $52.75.
Ticket for an adults = $7.25
Ticket for a student = $5.50
Let number of adults be A
Let number of students be S
Then, A + S = 8 (number of people in group)
And, A*7.25 + S*5.50 = 52.75 (sum of individual costs = total cost)
Substituting for A = 8 - S, from 1st eqn, into 2nd eqn gives us,
(8 - S)*7.25 + S*5.5 = 52.75
58 - 7.25S + 5.5S = 52.75
58 - 1.75S = 52.75
58 - 52.75 = 1.75S
S = 5.25/1.75 = 3
A = 8 - S = 5
There are 5 adults and 3 students