From the question;
The ticket per child costs $2
Three children go to see the show
A. We are to draw a bar diagram
From the bar diagram
The cost of ticke for 1 child = $2
The cost of ticket for 2 children = $4
The cost of ticket for 3 children = $6
This implies
If x is the cost of 3 children then
Therefore, the total cost of their tickets is $6