A total of

496 tickets were sold for the school play. They were either adult tickets or student tickets. The number of student tickets sold was three times the number of adult tickets sold. How many adult tickets were sold?

A+s=496

s=496-a

and we are also told that:

s=3a

Since s=s we can say:

3a=496-a add a to both sides

4a=496 divide both sides by 4

a=124

So 124 adult tickets were sold.

Since there were three times as many student tickets sold, you can write the equation C = 3A C being children tickets and A being adult tickets

to get the total number of tickets sold you add children and adults so the equation would be C + A = 496

this is a substitution problem. where you take what C equals in the first equation, and plug it into C for the second equation

(3A) + A = 496

4A = 496

A = 124

so you now know that 124 adult tickets where sold.