A) 2
im not sure about my answer but ihope it will help u
For this case we assume that the photo album is rectangular in shape and therefore the fabric too. By definition, the area of a rectangle is given by:

Where:
a: It is the length of the rectangle
b: It is the width of the rectangle
According to the problem data we have to:

Substituting:

We clear "a":

Thus, the length of the fabric is 
ANswer:
The length of the fabric is
A=<4.60,7.20>
b=<5.10,2.70>
The scalar product, or the inner product, or the dot-product, is by summing the products of the respective directions,
a.b=4.6*5.1+7.2*2.7
=23.46+19.44
=42.9
Answer is J because if 3 hours is $140 and 6 hours is $185 you calculate the difference. In this case $45 and divide it by 3, which is the difference between hours with those amounts, and answer is 15. And the only one with 15 is J.