There are 33 students in the band there are more 5th grade students than 3rd grade students there is an equal number of 3rd grade and fourth grade students how many third grade students are in the band

Use A for third graders, B for fourth graders, and C for fifth graders.

33 = A + B + C

Since there are 3 variables, you need to come up with two other equations to substitute in. 

C = 6 + A Since there are six more fifth graders than third graders. 

A = B Since there is an equal amount of third and fourth graders.

Since A is in both equations, then lets put each variable in terms of A. 

B = A

C = 6 + A

So:

A + A + A + 6 = 33

A + A + A = 27 Since you subtract 6 from both sides.

3A = 27 Since you combine all three A's. 

A = 9 Since you divide both sides by three. 

Therefore, since A is a number of third graders, there are 9 third graders.

(Sorry if there's any typos.