Atotal of 345 tickets were sold for the school play. they were either adult tickets or student tickets. the number of student tickets sold was two times the number of adult tickets sold. how many adult tickets were sold? 4 \[p

Write the system of equation based on the problem
"A total of 345 tickets that consists of adult tickets and students ticket were sold" could be written as:
∴ a + s = 345 (first equation)
"the number of student tickets sold was two times the number of adult tickets sold" could be written as:
∴ s = 2a  (second equation)

Solve the system of equation
Substitute 2a as s in the first equation
a + s = 345
a + (2a) = 345
3a = 345
  a = 345/3
  a = 115

There are 115 adult tickets sold.