Someone me and explain this question to me (the last question starting with a straw)

Each straw is  4-1/8 inches long.
You have one gigantic piece of straw material, 123-3/4 inches long.
How many straws can you cut it up to make ?

 ===>                    (123-3/4)  divided by  (4-1/8)            straws.

Each one costs  $0.015  to make.
So, once you find the number of short straws you have,
multiply

===>                 (the number of short straws) x ($0.015) .

That'll tell you how much it costs to make all of them. 

Now you know how to do it on your own.
If you don't get  30 straws  and  $0.45 , please try again.