Roy and S ally are building a 12 ft by 8 ft fence for there back yard. If the cost is $9 per square foot plus 7% tax, how much will this cost Roy and Sally?

Question

algebra question!! 

Answer 1

Usually fencing is done by linear feet, so I will do this problem both ways

 

Doing it with area:

First find the area of the rectangle (8 x 12) = 96 feet²

Next, multiply the area by the unit cost to get the pretax cost: 96 ft² x $9/ft² = $864

Now, multiply that number by the tax and add to the pretax cost to get the final cost: (0.07 x 864) + 864 = 60.48 + 864 = $924.48

 

Now if it is by linear feet:

First find the perimeter (8 + 12 + 8 + 12) = 40 feet

Then multiply the perimeter by the unit cost to get the pretax cost: 40 feet x $9/foot = $360

Finally, multiply the pretax cost by the tax and add that to the pretax cost to get the final cost: (360 x 0.07) + 360 = 25.20 + 360 = $385.20

Answer 2

First work out the area by multiplying the dimensions of the fence.

Now that you have the area, multiply this by the unit cost per square foot, to get the pre-tax cost of the fence.

Now calculate the tax by multiplying the pre-tax cost, by 7% or .07.  

After adding the tax to the pre-tax cost of the fence, you will have the total cost.

In summary,

(length)(height) = area

(area)(unit cost) = pre-tax cost

(pre-tax cost)(.07) = tax

pre-tax cost + tax = total.

Hope this helps.