133 adult tickets were sold.
Step-by-step explanation:
Given,
Total tickets sold for school play = 399
Let,
x represent the number of children tickets sold.
y represent the number of adult tickets sold.
According to given statement;
x+y=399 Eqn 1
x = 2y Eqn 2
Putting value of x from Eqn 2 in Eqn 1
Dividing both sides by 3
133 adult tickets were sold.
Keywords: linear equation, substitution method
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