Answer:
3 tier seats tickets
Explanation:
Let the friends that bought floor seats be x and let the friends that bought tier seats be y.
Thus;
x + y = 12 - - - (eq 1)
Floor seats tickets cost $15 each, and tier seats tickets cost $70 each. The total cost of the tickets was $345. Thus;
15x + 70y = 345 - - - (eq 2)
Let's make x the subject in eq (1)
x = 12 - y
Putting this for x in eq 2 gives;
15(12 - y) + 70y = 345
180 - 15y + 70y = 345
55y = 345 - 180
55y = 165
y = 165/55
y = 3
Put 3 for y in x = 12 - y to get;
x = 12 - 3
x = 9
Thus, they purchased 9 floor seats tickets and 3 tier seats tickets