Carol is building a screen door. the height of the door is one foot more than twice its width. what is the width of the door if the height is seven feet?

Hello,

A good method for solving this question is creating an equation to solve for the width of the door.

Let w = the width of the door
Let h = the height of the door

The height (h) is twice the width (2w) and one foot more (+1).
We can make the equation h = 2w + 1

Now, we are given that the height of the door is 7 feet, so h = 7.
We can simply plug in 7 for h in the equation to solve for w. 

So, we have h = 2w + 1
7 = 2w + 1
Subtract by 1 on both sides to get:
6 = 2w
Divide by 2 on both sides to get:
w = 3

The width of the door is 3 feet.

However, we should check out answer with the given question to make sure it checks out.

We are given that the height of the door is one foot more than twice its width, and the height of the door is 7 feet.

Twice the width is 6 feet, and one foot more than that is 7 feet. Our answer checks out.

The width of the door is 3 feet.

Hope this helps!

The answer would be (c)