Hi Deidei:
There are different ways to solve this problem. I'll show you one set-up.
We're asked to find how many adults tickets were sold. We're also asked to find how many student tickets were sold.
If we knew how many adult tickets were sold, we could easily calculate the number of student tickets by subtacting the adult tickets from the total tickets.
So, let's first find how many adult tickets were sold.
Pick a symbol to represent this unknown number of tickets. I'll pick x.
Write it down:
x = the number of adult tickets sold
Now we can write an expression that represents the number of student tickets sold.
805 - x = the number of student tickets sold
Does this make sense, so far?
To find the value of x, we use the money information to write an equation.
The revenue from selling the adult tickets is expressed by multiplying the number of tickets by their price; the talent show collected $4 for each adult ticket sold.
4x = the revenue from selling all of the adult tickets
Likewise, we can write an expression for the money collected for the student tickets; they each cost $3.
3(805 - x) = the revenue from selling all of the student tickets
The sum of these two revenues is given, so we write an equation.
4x + 3(805 - x) = 1740
That's the set-up. Your son should already know how to solve equations like this.
Once he finds x (the number of adult tickets), he can subtract it from 805 to find the number of student tickets.
Let us know, if more help or clarification is needed. When replying, please post whatever work that your son can do, or try to explain why he's stuck, so that we might determine where to continue helping.
Cheers ~ Mark
PS: I cannot recommend paying for online tutoring because there are so many good sites available for free. If somebody wants to pay to get more personalized service, then I recommend that they spend their money on a local tutor who can meet face-to-face.