How can you represent how the sets of whole number,integers,and rational number are realated to each other ?

Whole numbers are simply the numbers: 0, 1, 2, 3, 4, 5, ... and so on. Actually whole numbers are natural numbers and zero.

Integers are natural numbers, zero and negative numbers: ...,-5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, ...  

Rational numbers that can be made by dividing two integers. For example,

You can see that each whole number is integer number and each integer is a rational number, then

The area of the plot is 600 (20x30) and it needs to be 1200 (600x2)
only the width is changed so you divide it by the length which is 30 
1200 divided 30 is 40 so the answer is 40 (another way is to just multiply the width by 2 since it's the only thing changing)

hope this helps :)