To solve the system of equations, we have:
- \( x + y = 80 \) (Equation 1)
- \( 6x + 4y = 420 \) (Equation 2)
Where:
- \( x \) is the number of adult tickets sold.
- \( y \) is the number of child tickets sold.
Let's analyze the options given for their validity against these equations:
-
Testing (20, 60):
- \( x = 20 \) and \( y = 60 \)
- From Equation 1: \( 20 + 60 = 80 \) (correct)
- From Equation 2: \( 6(20) + 4(60) = 120 + 240 = 360 \) (not correct)
-
Testing (30, 50):
- \( x = 30 \) and \( y = 50 \)
- From Equation 1: \( 30 + 50 = 80 \) (correct)
- From Equation 2: \( 6(30) + 4(50) = 180 + 200 = 380 \) (not correct)
-
Testing (40, 40):
- \( x = 40 \) and \( y = 40 \)
- From Equation 1: \( 40 + 40 = 80 \) (correct)
- From Equation 2: \( 6(40) + 4(40) = 240 + 160 = 400 \) (not correct)
-
Testing (50, 30):
- \( x = 50 \) and \( y = 30 \)
- From Equation 1: \( 50 + 30 = 80 \) (correct)
- From Equation 2: \( 6(50) + 4(30) = 300 + 120 = 420 \) (correct)
The only solution that satisfies both equations is (50, 30).
This means that 50 adult tickets and 30 child tickets were sold that day at the movie theater.