Math questions

Here are some questions I am having a lot of trouble with..can someone help me?
BE SURE TO WRITE AN EQUATION

*The concession stand sold 26 hot dogs and hamburgers for a total of $29.50. The hot dogs cost $0.95 and the hamburgers cost $1.25. How many...

hotdogs and how many hamburgers were sold?

*The park ranger is fencing in an area that is 24ft wide and 36ft long. The fence posts will be 3ft apart. How many fence posts will be needed?

*The doughnut shop is having a special on doughnuts. The first dozen is $3.60, and each additional dozen is $1.00 off. The breakfast club paid $21.80. How many dozens did the club buy?

Thank you.

The First Problem:

let x = the number of hot dogs and let y = the number of hamburgers.
The concession stand sold 26 hot dogs and hamburgers altogether
therefore, x + y = 26 ... (1)

And they received a total of $29.50
therefore, 0.95x + 1.25y = 29.5 ... (2)

Re-arrange (1) to make why the subject.
y = 26 - x ... (3)

Sub this into (2)
0.95x + 1.25y = 29.5
0.95x + 1.25(26 - x) = 29.5
0.95x +32.5 - 1.25x = 29.5
0.95x - 1.25x = 29.5 - 32.5
-0.3x = -3
x = 10
Therefore 10 hamburgers were sold
Sub x = 10 into (3)

y = 26 - x
= 26 - 10
= 16

The Second Problem:

Assuming that this area is rectangular, the number of posts needed is simply the perimeter of this rectangle divided by 3 (because the are 3 metres per post)

Perimeter = 2(Width + Length)
= 2(24 + 36)
= 120 metres

Number of posts = 120 (metres) / 3 (metres/post)
= 40 posts.

The Third Problem:

The number of additional dozens bought is $21.80 - $3.60 (the cost of the first dozen) and then divide that result by $2.60 (the cost of each additional dozen).

Number of additional doughnuts = (21.8 - 3.6)/2.6
= (18.2)2.6
= 7
Therefore, the number of dozens bought by the breakfast club is 8 ie 7 + 1 (the first dozen).

Just thought I should point out, it's 10 hotdogs... (he wrote hamburgers)

Ooops hehe. Thanks ty. I didn't see that.

THANK YOU SO MUCH!!