Notice that the given info consists of boundary lines for an area in the xy plane. We are interested ONLY in values of x and y that are 0 or greater (positive). Graph 5x + 3y

37 and 3x + 5y less than or equal to 35.
Find the points of intersection of all four straight lines (including the x- and y-axes). There will be 4 such points (incl. the origin).
Next, evaluate the objective function 2x + 14y at each of these 4 points. Which of the four results is the largest? the smallest? Label them as 'maximum' and 'minimum.'
Questions? Just comment on this discussion.
Answer:
If you multiply the length and width it's already more than D and b so it's between 41 and 71 , I believe it's 71 though
The best way to multiply complicated problems mentally* is to break them into chunks.
Start with 20 times 8 to get 160, and then 8 times 5 to get 40. Add these together to get 200. 200 times 3 is 600, and 20 times 200 is 4000. Add these together to get your final answer, 4600.
In other words 8 x 20 + 8 x 5 = 200 200 x 3 + 200 x 20 = 4600
*I assumed you meant mentally, because otherwise you'd just multiply longhand, multiplying two of the three numbers and then multiplying their product with the third.
The answer is actually cube A