\
Let
be number of adult tickets which costs
.
Let
be the number of child tickets which costs
.
Let
be the number of senior citizen tickets which costs
.
Since total number of seats is
,
.
Since the total revenue is
if all seats are sold ,
.
Twice as many children’s tickets were sold as adult tickets, therefore
.
From the data ,the system of equations are
.
Substiute
in equation
.

Substiute the value
in equation
.

Multiple to each side the equation
by
and add to the equation
to eliminate
.
.

Substiute
in equation
.

Substiute
in equation
.

The solution is
and
.
Therefore there are
adults,
children and
senior citizens went to theater that day.
There are
adults,
children and
senior citizens went to theater that day. \ \