A certain type of siding for a house costs $10.50...

A certain type of siding for a house costs $10.50 per square yard. What does it cost for the siding for a wall 4 yards wide and 60 feet long?

A. $800
B. $840
C. $2520
D. $3240
E. $5040

The OA is B.

To solve this PS question, I just need to find the total area in yards of the siding that has 4 yards wide and 60 feet long, right?

I need to convert the 60 feet to yards and then determine the area and get the total cost multiplying the total square yards by $10.50.

I appreciate if any expert explains it to me. Thank you so much.

Hi AAPL,
Let's take a look at your question.

Since the cost is given according to per square yard, therefore we will convert the length in yards as well.

We know that:
$$1\ ft=\frac{1}{3}yards$$
$$60\ ft=60\times\frac{1}{3}yards=20\ yards$$
$$Length=20\ yards$$
$$Width=4\ yards$$
$$Area\ of\ wall=Length\times Width$$
$$Area\ of\ wall=20\times4=80\ square\ yards$$
Now, we can find the cost of siding on the wall.
$$Cost\ of\ siding\ per\ square\ yard=10.50$$
$$Cost\ of\ siding\ on\ 80\ square\ yards=80\times10.50=840$$
Therefore, Option B is correct.

Hope it helps.
I am available if you'd like any follow up.