that's right the way you have it right now in the picture all adds up to 65
Number 5a. is 26.78 and 5b. is 8.5
If Joe collected 94 stamps which are in April May and June, we could make an equation like this: A + M + J = All stamps
Plug in the values:

Isolate J:

Combine like terms:

He collected 33 stamps in June.
A = 1/2 h(b + x)
2a = h(b + x)
2a/h = b + x
x = 2a/h - b